Sunflower bee pollen jam and preparation method thereof

Abstract

The invention discloses sunflower bee pollen jam and a preparation method thereof, and belongs to the technical field of bee product deep processing. The preparation method comprises the following steps: mixing pretreated sunflower bee pollen, red dates and honey, adding purified water, and pulping to obtain pulp; adding xylitol, citric acid and vitamin A, and adding pectin until the content of soluble solids is 40-43% during heating concentration; the sunflower and melissa jam is obtained. The prepared bee pollen jam is palatable in sourness and sweetness and rich in flower and fruit fragrance, meanwhile, vitamin A is added, nutrition can be enhanced, the market blank of bee pollen deep processing products is filled up, a natural and safe dietary supplement scheme is provided for people lacking vitamin A, and the bee pollen jam has high commercial value and is worthy of popularization and application. And an efficient and healthy new way is provided for deep processing of bee pollen.

Description

Technical Field

[0001] The invention relates to the technical field of deep processing of bee products, in particular to a sunflower bee pollen jam and a preparation method thereof. Background Art

[0002] Traditional bee pollen processing technology mostly uses high-temperature sterilization or direct drying. Although it can extend the shelf life, it leads to a large loss of bioactive substances such as polyphenols and flavonoids. In addition, unfermented bee pollen contains natural bitter substances, which makes it bitter in taste and has low consumer acceptance. Existing bee pollen products are in a single form, mainly capsules or powders, and lack deep-processed foods that are both nutritious and flavorful. In addition, vitamin A deficiency (VAD) is a global public health problem. Existing solutions rely on chemically synthesized vitamin A supplements, which have defects such as low absorption rate and high risk of side effects.

[0003] The most widely used practice for preventing VAD is to regularly supplement with high doses of vitamin A, which can be provided alone or as a component of a multivitamin supplement when the diet does not provide enough vitamin A. Studies have found that oral vitamin A absorption reaches 70-90%. Therefore, the development of new bee pollen products that can provide vitamin A is of great significance for expanding the bee pollen consumer market and preventing VAD. Summary of the invention

[0004] The purpose of the present invention is to provide a sunflower bee pollen jam and a preparation method thereof to solve the problems existing in the above-mentioned prior art. The present invention prepares a bee pollen jam with added vitamin A, which has a suitable sweet and sour taste, a floral and fruity aroma, and a delicate texture.

[0005] Technical solution 1: A method for preparing sunflower bee pollen jam, comprising the following steps: mixing pre-treated sunflower bee pollen, red dates and honey, adding purified water to pulp to obtain a slurry; adding xylitol, citric acid and vitamin A, and adding pectin during heating and concentration until the soluble solid content is 40%-43%; obtaining the sunflower bee pollen jam.

[0006] The honey includes jujube flower honey.

[0007] Furthermore, the pretreatment includes inoculating composite lactic acid bacteria into the sunflower bee pollen for fermentation, and the composite lactic acid bacteria accounts for 10% of the mass of the sunflower bee pollen.

[0008] Furthermore, the preparation method of the composite lactic acid bacteria comprises: compounding Lactobacillus plantarum and Lactobacillus casei in a volume ratio of 3:1.

[0009] Furthermore, the fermentation is carried out at 37° C. for 72 hours.

[0010] Furthermore, the sunflower bee pollen, red dates and honey are mixed in a mass ratio of 2:1:1.

[0011] Furthermore, the added amount of xylitol is 7% of the mass of the slurry; the added amount of citric acid is 0.3% of the mass of the slurry; the added amount of vitamin A is 0.2% of the mass of the slurry; and the added amount of pectin is 0.6% of the mass of the slurry.

[0012] Furthermore, the soluble solid content is 41.33%.

[0013] Technical solution 2: Sunflower bee balm jam prepared by the preparation method.

[0014] The present invention adopts single factor combined with orthogonal test to obtain bee pollen jam, the jam has moderate hardness, good adhesion and chewiness, water content of 49.49%, soluble solids of 41.33%, total sugar of 32.21%, and no total colony count and mold are detected. The bee pollen jam has a suitable sweet and sour taste, a flower and fruit aroma, a uniform and delicate texture, and can obtain a uniform coating when applied.

[0015] The present invention discloses the following technical effects:

[0016] The present invention adopts single factor combined with orthogonal experiment to develop bee pollen jam with good sensory organs and capable of providing vitamin A. The present invention ferments bee pollen with lactic acid bacteria, combines natural raw materials such as red dates and honey (red dates are rich in bioactive compounds, such as polyphenols, flavonoids, polysaccharides and saponins, and have strong anti-oxidation, antibacterial, anti-melanin production, anti-inflammatory and other biological activities; honey is a common material of medicinal and edible origin, and is first recorded in "Shennong's Herbal Classics" as a traditional Chinese medicine, and "Compendium of Materia Medica" lists five benefits of honey, namely "clearing heat", "tonifying the middle", "detoxifying", "moistening dryness" and "stopping the pain of heart and abdominal muscle sores"), develops bee pollen jam with sweet and sour taste and fortified nutrition, fills the market gap of bee pollen deep-processing products, and provides a natural and safe dietary supplement for people with vitamin A deficiency, which has great commercial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1The effects of fermentation with different strains on the pH value (A), reducing sugar content (B), total phenol content (C), and total flavonoid content (D) of sunflower bee pollen; different lowercase letters represent significant differences (p<0.05);

[0019] Figure 2 Effects of different bacterial species ratios (A), lactic acid bacteria inoculation amount (B), water addition amount (C), fermentation time (D), and fermentation temperature (E) on the sensory score, pH value, and viable count of sunflower bee pollen; different lowercase letters represent significant differences (p<0.05);

[0020] Figure 3 This is the preparation process of bee pollen jam in Example 2;

[0021] Figure 4 Sensory scores of bee pollen jam with different raw material ratios (A), xylitol addition (B), citric acid addition (C), vitamin A addition (D) and pectin addition (E). DETAILED DESCRIPTION

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0024] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0025] Example 1 Pretreatment of Sunflower Bee Pollen

[0026] 1. Experimental Reagents

[0027] Sunflower bee pollen was purchased from beekeepers and was tested for palynology. Edible alcohol was purchased from Hualin Co., Ltd. The main experimental reagents are shown in Table 1.

[0028] Table 1 Experimental reagents

[0029]

[0030] 2. Experimental Methods

[0031] 2.1 Pretreatment of sunflower bee pollen

[0032] Spray the sunflower bee pollen with 75% edible alcohol, stir it constantly to evenly distribute the alcohol, and seal it for 2 hours. Then, cover the surface of the bee pollen with sterile gauze and place it in a drying oven at 40°C to remove the alcohol and dry it for subsequent use.

[0033] 2.2 Determination of lactic acid bacteria growth curve

[0034] Use 6 kinds of freeze-dried lactobacillus powders of Lactobacillus bulgaricus, Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei and Lactobacillus casei, after thawing, inoculate in MRS broth according to inoculum size 1%, and be placed in constant temperature incubator and carry out activation culture for 12h. Subsequently, the activated bacterial species is transferred to MRS liquid nutrient medium, and cultivated for 24h under each bacterial species optimum growth temperature. Measure absorbance at 600nm, calibrate with blank culture medium. In 0-24h, sample and measure the OD value of bacterial liquid every 2h. Determine that the logarithmic growth phase of Lactobacillus bulgaricus, Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei and Lactobacillus casei is in cultivation 2-8h, 4-16h, 2-12h, 2-12h, 6-14h and 2-12h respectively.

[0035] 2.3 Screening of fermentation strains

[0036] Single strain fermentation: 6 strains were cultured to the logarithmic growth phase, and the sterilized sunflower bee pollen was placed in a constant temperature incubator for fermentation under the conditions of 45% water addition, 7% inoculation, and 48h fermentation. The number of live bacteria in the fermented sunflower bee pollen was determined to conduct preliminary screening of the strains.

[0037] (1) Detection of indicators during fermentation of a single strain

[0038] After activating the strains obtained by preliminary screening, the sterilized sunflower bee pollen was placed in a constant temperature incubator for fermentation under the conditions of 45% water addition and 7% inoculation. Samples were taken at 0, 24, 48, 72, and 96 hours respectively to test the pH value, reducing sugar content, total phenol content, and total flavonoid content of the samples.

[0039] (2) Composite bacterial fermentation

[0040] 45% sterile water was added to the sterilized sunflower bee pollen, and the most suitable bacterial strain combination was screened at a ratio of 1:1 (volume ratio) and a 7% inoculation amount, a fermentation temperature of 37° C., and a fermentation time of 48 h.

[0041] 2.4 Single factor experiment of fermentation of sunflower bee pollen by compound lactic acid bacteria

[0042] The sterilized sunflower bee pollen was taken for later use. The number of viable bacteria, pH value and sensory score were used as indicators. A single-factor fermentation experiment was carried out on the sunflower bee pollen by controlling the strain ratio (Lactobacillus plantarum: Lactobacillus casei), strain inoculation amount (%), water addition amount (%), fermentation time (h) and fermentation temperature (℃). The experimental design is shown in Table 2.

[0043] Table 2 Single factor experimental design for fermentation process optimization

[0044]

[0045] 2.5 Orthogonal experiment of fermentation of sunflower bee pollen by compound lactic acid bacteria

[0046] On the basis of the single factor experiment, sensory scores and viable bacteria counts were used as evaluation indicators. The experimental design is shown in Table 3. Taking viable bacteria counts and sensory scores as indicators, fermentation temperature (A), bacterial inoculation amount (B), water addition amount (C), bacterial strain ratio (D), and fermentation temperature (E) were selected as factors for orthogonal experiments to determine the optimal fermentation conditions for lactic acid bacteria fermentation of sunflower bee pollen.

[0047] Table 3 Orthogonal design level table for fermentation process optimization

[0048]

[0049]

[0050] 2.6 Verification Experiment

[0051] Sunflower bee pollen was fermented under the optimal fermentation conditions, and its live bacteria count was determined and sensory evaluation was performed. It was compared with bee pollen fermented under other fermentation conditions to verify the sensory quality of bee pollen fermented under the optimal fermentation conditions.

[0052] 2.7 Determination method

[0053] (1) Counting of live lactic acid bacteria

[0054] The counting of live lactic acid bacteria is based on GB4789.35-2016, and the colony count is expressed as LogCFU / g.

[0055] (2) pH determination of fermented bee pollen

[0056] Bee pollen and distilled water were mixed evenly at a ratio of 1:5 (g / v), and the pH was directly measured at room temperature using a pH meter.

[0057] (3) Determination of reducing sugar content

[0058] The reducing sugar content was determined by 3,5-dinitrosalicylic acid (DNS) colorimetric method.

[0059] (4) Determination of total phenolic content and total flavonoid content

[0060] Weigh 4g of sunflower bee pollen before and after fermentation, use 80% methanol for ultrasonic extraction at a solid-liquid ratio of 1:10 for 1h, then heat reflux extraction for 2h, take out the extract, centrifuge at 4000r / min for 10min, take the supernatant and dilute to 100mL to obtain bee pollen methanol extract. The total phenol content of bee pollen is determined by the Folin-Ciocalteu method and expressed in milligrams of gallic acid equivalents (mg / g). The total flavonoid content of bee pollen is determined according to Ghosh's method (Ghosh K, Ray M, Adak A, et al. Role of probiotic Lactobacillus fermentum KKL1 in the preparation of a rice based fermented beverage [J]. Bioresource Technology, 2015, 188: 161-168.), expressed in milligrams of rutin equivalents (mg / g).

[0061] (5) Sensory evaluation of fermented bee pollen

[0062] Ten students were selected to form a sensory evaluation team after unified sensory training. The color, texture, flavor, and taste of the fermented bee pollen were evaluated according to the scoring criteria, and a comprehensive score was finally obtained. The sensory scoring criteria are shown in Table 4.

[0063] Table 4 Sensory scoring criteria for fermented bee pollen

[0064]

[0065]

[0066] 2.8 Data Processing

[0067] Each experiment was repeated three times, and the experimental data were analyzed using IBM SPSS Statistics 26 software. The experimental results were presented as mean ± standard error and graphed using GraphPad Prism 8 software.

[0068] 3. Results and Analysis

[0069] 3.1 Screening of lactic acid bacteria and determination of compound fermentation strains

[0070] (1) Growth ability of different bacterial species in sunflower bee pollen

[0071] The experimental results are shown in Table 5, and there are significant differences in the growth conditions of the four strains (p < 0.05). Different lactic acid bacteria have different adaptability to the growth environment, and factors such as the reduction of substrate pH value and the consumption of nutrients may affect the growth of lactic acid bacteria. The viable counts of Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus plantarum and Lactobacillus paracasei after fermentation for 48h were 8.06LogCFU / g, 7.25LogCFU / g, 7.41LogCFU / g and 7.30LogCFU / g, respectively, all exceeding 7LogCFU / g, while the viable counts of Lactobacillus bulgaricus and Lactobacillus acidophilus were only 6.61LogCFU / g and 6.25LogCFU / g, respectively. Therefore, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus plantarum and Lactobacillus paracasei were selected for further study.

[0072] Table 5 Results of viable bacterial counts of sunflower bee pollen fermented by different strains

[0073]

[0074] Note: Different lowercase letters indicate significant differences among the groups (P<0.05).

[0075] (2) pH tolerance, hypoglycemic ability and effects of different bacterial strains on antioxidant substances in sunflower bee pollen

[0076] Depend on Figure 1 It can be seen from A that with the extension of fermentation time, the pH value of each group showed a downward trend. Among them, the pH value of sunflower bee pollen fermented by Lactobacillus plantarum decreased rapidly, and the final pH value was about 3.3. The pH values ​​of Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus paracasei and Lactobacillus casei at 96h were 3.73, 3.36, 3.98 and 3.64 respectively. This shows that the four lactic acid bacteria have different tolerance to pH values. Among them, Lactobacillus plantarum can lower the pH value of the fermented bee pollen system compared with the other three lactic acid bacteria, indicating that it can tolerate a lower pH environment, has a higher pH tolerance, and can withstand the acidic conditions in the stomach or intestines. Figure 1 From B, we can see that the reducing sugar content of each group showed a downward trend, and the reducing sugar content of fermented sunflower bee pollen was significantly lower (p < 0.05) than that of unfermented bee pollen. The reducing sugar content of Lactobacillus plantarum dropped sharply in 24-72h, indicating that the lactic acid bacteria consumed a large amount of carbon source during this period, and the change in reducing sugar content tended to be stable after 72h. This may be because too much acid accumulated in the first 72h, resulting in the inhibition of bacterial growth, thereby affecting the bacteria's continued consumption of sugars and acid production. In addition, the large accumulation of other metabolic end products such as diacetyl, acetaldehyde and acetyl may also affect the growth of bacteria. Combined with Figure 1As we know, since Lactobacillus plantarum can tolerate a lower pH environment, the reducing sugar content at the endpoint is the lowest, which is 47.68g / 100g.

[0077] Depend on Figure 1 From the C, it can be seen that the total phenol content of sunflower bee pollen fermented by Lactobacillus plantarum and Lactobacillus casei rose rapidly within 0-24h and reached the maximum value of 4.27mg / g and 3.92mg / g respectively; the total phenol content after fermentation by Lactobacillus rhamnosus reached the maximum value of 3.68mg / g at 48h; the total phenol content after fermentation by Lactobacillus paracasei reached the maximum value of 3.64mg / g at 72h. However, with the extension of fermentation time, the content of phenolic substances in bee pollen fermented by each strain decreased. In natural form, phenolic compounds are combined with sugars, which reduces their availability to organisms. During the fermentation process, the proteolytic enzymes produced by the fermented strains hydrolyze complex phenols into phenolic substances with simple structure, strong biological activity and easy absorption. With the increase of fermentation time, the growth of lactic acid bacteria is restricted, which may cause lactic acid bacteria to be unable to continue to metabolize and convert phenolic substances. At the same time, other metabolites, such as organic acids and enzymes, may be produced during the metabolism of lactic acid bacteria. These metabolites may react with phenolic substances, causing them to be oxidized and reduced or to form complexes, thereby reducing the total phenolic content. Figure 1 It can be seen from D that the total flavonoids content of sunflower bee pollen fermented by the four lactic acid bacteria first showed an upward trend, and the total flavonoids content of the four lactic acid bacteria reached the maximum value at 72h, which were 6.06mg / g, 5.45mg / g, 5.82mg / g and 5.93mg / g respectively. With the increase of fermentation time, the total flavonoids content gradually decreased.

[0078] (3) Composite strain screening

[0079] According to the result after single bacteria screening, it is found that plant lactobacillus fermentation performs better in pH tolerance, hypoglycemic, total phenol content, so plant lactobacillus is selected to be composited with Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei respectively.As shown in Table 6, compared with single strain fermentation, the viable count of composite strain fermentation increases, all exceeds 8LogCFU / g, and the viable count after plant lactobacillus and Lactobacillus casei composite is the highest, which is 8.49LogCFU / g.In commercial lactobacillus products, when the viable count reaches 8LogCFU / g, the beneficial function of lactic acid bacteria can be fully utilized.Therefore the present invention selects plant lactobacillus and Lactobacillus casei to composite and carry out subsequent experiments.

[0080] Table 6 Results of viable bacterial counts of composite bacterial fermentation of sunflower bee pollen

[0081]

[0082]

[0083] Note: Different lowercase letters indicate significant differences among the groups (P<0.05).

[0084] 3.2 Single factor experimental results

[0085] (1) Proportion of bacterial strains

[0086] Effects of different bacterial strain ratios on sunflower bee pollen Figure 2 As shown in A. When the ratio of Lactobacillus plantarum is higher, the number of live bacteria in fermented bee pollen is also higher. When the ratio of Lactobacillus plantarum to Lactobacillus casei is 2:1, the number of live bacteria reaches the highest point, which is 7.90LogCFU / g. At this time, the taste of fermented bee pollen is appropriately sweet and sour, the color is bright golden yellow, the floral fragrance is strong, and the sensory score is 76.97. As the ratio of Lactobacillus plantarum increases, the number of live bacteria decreases. There is no significant difference in the number of live bacteria when the ratio of Lactobacillus plantarum to Lactobacillus casei is 5:1 and 1:1 (p>0.05), but from the perspective of sensory scores, 5:1 is the best choice. In summary, the bacterial strain ratios of 2:1, 3:1 and 5:1 were taken for subsequent experiments.

[0087] (2) Inoculation volume

[0088] Effects of different bacterial inoculation rates on sunflower bee pollen Figure 2 As shown in B. The inoculation amount of lactic acid bacteria has a great influence on the number of live bacteria, sensory score and pH value of fermented bee pollen. With the increase of inoculation amount, the number of live bacteria shows a trend of rising and then falling. When the inoculation amount is 3%, the number of fermented bee pollen of bee pollen is small, the fermentation degree is low, and the acid production is small. At this time, the bitterness and astringency of bee pollen are obvious, and the sensory score is the lowest, only 63.26. When the inoculation amount reaches 5%, the number of live bacteria reaches the highest value, which is 7.82LogCFU / g. At this time, the sensory score of bee pollen is 74.54, with a sweet and sour taste, and a floral and slightly sweet aroma. When the inoculation amount is 15%, the pH of the system is too low, resulting in the bee pollen taste being too sour and having a pungent smell. At this time, the number of live bacteria is only 6.92LogCFU / g, which is not significantly different from the number of live bacteria when the inoculation amount is 10% (p>0.05). In summary, the inoculation amounts of 5%, 7% and 10% of the strains were taken for subsequent experiments.

[0089] (3) Amount of water added

[0090] Effects of different water addition amounts on sunflower bee pollen Figure 2As shown in C. Water is an important factor affecting the growth and metabolism of lactic acid bacteria. When the amount of water added is less than 40%, the bee pollen tissue state is relatively dry and granular. The insufficient water content of the system leads to insufficient fermentation, and the bee pollen still retains a heavy bitter taste, which makes the sensory score of the bee pollen low. When the amount of water added is 50%, the live bacteria count (8.40LogCFU / g) and sensory score (78.71) of bee pollen are both the highest. When the amount of water added is greater than 50%, the water content is too high, the bee pollen tissue state is too thin, the taste is sour and slightly bitter, and the sensory score is reduced. This may be because adding too much water will dilute the nutrients in the fermentation, such as carbon sources and nitrogen sources, which lactic acid bacteria need to grow and reproduce. If the concentration of nutrients in the system is too low, the reproductive capacity of lactic acid bacteria will be limited, which will lead to a decrease in the number of lactic acid bacteria. In summary, the water addition amounts of 40%, 45% and 50% were taken for subsequent experiments.

[0091] (4) Fermentation time

[0092] The results are as follows Figure 2 As shown in D, the sensory score of fermented bee pollen shows a trend of first rising and then falling with the increase of fermentation time. When the fermentation time is less than 36h, the fermentation time of bee pollen is short, the acid production is small, and the fermentation degree is insufficient. Therefore, lactic acid bacteria cannot make the fermentation system form a special flavor, thereby affecting the sensory score of bee pollen. Within the fermentation time range of 36-72h, the pH value of bee pollen is low, the number of viable bacteria is high, and the sensory scores are 70.97, 74.84 and 73.84, respectively, which are significantly different from other fermentation time groups (p < 0.05). When the fermentation time exceeds 72h, due to the long fermentation time, bee pollen has a pungent sour taste and unpleasant odor, and the taste is too sour, and the sensory score is reduced. In addition, due to the long fermentation time, the nutrients in the system are consumed in large quantities, the growth and development of lactic acid bacteria are restricted, and the number of viable bacteria in the system is reduced. In summary, the fermentation time of 36h, 48h and 72h was taken for subsequent experiments.

[0093] (5) Fermentation temperature

[0094] Effects of different fermentation temperatures on sunflower bee pollen Figure 2 As shown in E. When the fermentation temperature was 37°C, the number of viable bacteria (7.00LogCFU / g) and the sensory score (76.04) reached the highest. When the fermentation temperature was 35°C and 39°C, the number of viable bacteria was 6.62LogCFU / g and 6.60LogCFU / g, respectively, which was significantly different from the fermented bee pollen at 33°C and 41°C (p < 0.05). From the results, it can be seen that when the fermentation temperature is 37°C, the growth and metabolic capacity of the composite bacteria reaches the highest, the metabolic rate is the fastest, and it can more effectively utilize nutrients for growth and production of lactic acid. Therefore, the fermentation temperature of 37°C was selected for subsequent experiments.

[0095] 3.3 Orthogonal experimental results

[0096] The experimental results are shown in Table 7. The fermentation conditions selected by the single-factor experiment were optimized by designing an orthogonal experiment to obtain the optimal fermentation conditions. From the R value of the viable bacteria count, it can be seen that the order of the five factors affecting the viable bacteria count of bee pollen is fermentation temperature > fermentation time > water addition > strain ratio (Lactobacillus plantarum: Lactobacillus casei) > inoculation amount. According to the range analysis, the optimal fermentation condition is A 2 B 2 C 3 D 3 E 2 The order of influence on the sensory score of bee pollen is fermentation time > inoculation amount > bacterial species ratio (Lactobacillus plantarum: Lactobacillus casei) > water addition amount > fermentation temperature. The best fermentation condition is A 3 B 2 C 3 D 2 E 3 The fermentation temperature has a greater impact on the number of viable bacteria than on the sensory score, so factor A is A. 2 When the water addition amount is 50%, the number of live bacteria is higher, but the amount of water is too much at this time, which leads to a decrease in the sensory score of bee pollen. Considering the sensory score comprehensively, the water addition amount is selected as 45%, that is, factor D is D 2 The fermentation time has a greater impact on the sensory score than on the number of viable bacteria, so factor E is E 3 In summary, the best fermentation conditions for sunflower bee pollen are A 2 B 2 C 3 D 2 E 3 That is, the fermentation temperature is 37°C, the ratio of Lactobacillus plantarum to Lactobacillus casei is 3:1, the inoculation amount is 10%, the amount of water added is 40%, and the fermentation time is 72h.

[0097] Table 7 Orthogonal experimental results of sunflower bee pollen fermentation

[0098]

[0099]

[0100] In summary, the optimal fermentation conditions for sunflower bee pollen are: fermentation temperature 37°C, Lactobacillus plantarum: Lactobacillus casei 3:1, inoculation amount 10%, water addition amount 40%, and fermentation time 72h. Under the optimal fermentation conditions, fermented sunflower bee pollen is bright golden yellow, has a pleasant aroma, tastes sweet and has a special flavor after lactic acid bacteria fermentation, has a smooth texture and no obvious particles, has a viable count of 8.62LogCFU / g, and a sensory score of 85.38.

[0101] Example 2 A method for preparing bee pollen jam

[0102] 1. Materials and Reagents

[0103] 1.1 Raw materials and reagents

[0104] The fermented sunflower bee pollen was prepared according to the best scheme of Example 1; jujube nectar (jujube nectar is used to represent honey in this example) was purchased from the Bee Products Application Technology Research Center of Northwest University; red dates were purchased from Ruoqiang Red Dates Industrial Base; vitamin A, citric acid, pectin, and xylitol were all food grade and purchased from Zhejiang Yinuo Biotechnology; plate count medium and potato dextrose agar were purchased from Beijing Aoboxing Biotechnology Co., Ltd.; DNS reagent was purchased from Feijing Biotechnology Co., Ltd.

[0105] 1.2 Instruments and Equipment

[0106] The experimental equipment and instruments are shown in Table 8.

[0107] Table 8 Experimental equipment and instruments

[0108]

[0109] 2. Experimental Methods

[0110] 2.1 Preparation process

[0111] The preparation process of bee pollen jam is as follows Figure 3 shown.

[0112] 2.2 Operation points

[0113] (1) Raw material slurry preparation

[0114] Select large, oval, and undamaged red dates, wash them, soak them in clean water for 12 hours, pre-cook them, soften them completely, remove the cores, and set aside. Red dates, date nectar, and fermented sunflower bee pollen are mixed in proportion, and pure water of 1 times the mass of the raw materials is added, and the slurry is obtained by beating, and the slurry is fine and uniform.

[0115] (2) Preparation and concentration

[0116] The slurry, xylitol, citric acid and vitamin A are mixed in a certain mass ratio, heated and boiled with continuous stirring to make the jam in a boiling state, and a certain mass ratio of dissolved pectin is slowly added, and the mixture is continuously heated and concentrated until the soluble solid content of the jam is 40-43%, and the concentration is completed when the jam has a wall-hanging phenomenon.

[0117] (3) Filling and sealing

[0118] The container must be sterilized before filling. Put the jam into the container while it is still hot and seal it immediately, leaving a certain amount of head space between the jam and the bottle mouth.

[0119] (4) Sterilization and cooling

[0120] Put the filled jam in boiling water for 5 minutes and get the finished product after cooling.

[0121] 2.3 Single Factor Experiment

[0122] Taking sensory score as an indicator, a single factor experiment was conducted by controlling the raw material ratio (fermented sunflower bee pollen: red dates: jujube honey), xylitol addition (%), citric acid addition (%), vitamin A addition (%), and pectin addition (%). The experimental design is shown in Table 9.

[0123] Table 9 Single factor experimental design of bee pollen jam

[0124]

[0125] 2.4 Orthogonal experiment

[0126] On the basis of the single factor experiment, sensory scores and viable bacteria counts were used as evaluation indicators, raw material ratio (A), xylitol addition (B), citric acid addition (C), and vitamin A addition (D) were selected as factors, and sensory scores were used as indicators to conduct orthogonal experiments to determine the optimal preparation conditions of the product. The experimental design is shown in Table 10.

[0127] Table 10 Orthogonal design level table of bee pollen jam

[0128]

[0129] 2.5 Quality Inspection

[0130] The final product was tested for color, texture (hardness, adhesion, cohesion, stickiness and chewiness), physicochemical indicators (soluble solids, moisture content and total sugar content) and microbiological indicators (total colony count and mold).

[0131] 2.6 Determination method

[0132] (1) Sensory evaluation

[0133] Ten students were selected to form a sensory evaluation team after unified sensory training. The color, texture, flavor, taste, and spreadability were evaluated according to the scoring criteria in Table 11, and a comprehensive score was finally obtained.

[0134] Table 11 Sensory scoring criteria for bee pollen jam

[0135]

[0136] (2) Determination of color and texture

[0137] The color of the jam was measured using a handheld colorimeter, where L* represents lightness, a* represents redness and greenness, and b* represents yellowness and blueness. A texture analyzer was used to conduct a total texture analysis (TPA) of the hardness, adhesion, cohesion, stickiness and chewiness of the bee pollen jam. The test conditions were as follows: a P36R test head was used, the pre-, mid- and post-test rates were all 1 mm / s, the sample deformation was set to 50%, and the trigger force was 5 g.

[0138] (3) Determination of physical and chemical indicators and microbiological indicators

[0139] The determination of soluble solids content of jam shall refer to GB / T 10786-2016 and be carried out using the Abbe refractometer method; the moisture content shall be directly determined using a moisture detection instrument; the total sugar content shall be determined using the DNS method; the total colony count and mold content shall be determined in accordance with GB 4789.2-2022 and GB 4789.15-2016, respectively.

[0140] 2.7 Data Processing

[0141] Each experiment was repeated three times, and the experimental data were analyzed using IBM SPSS Statistics 26 software. The experimental results were presented as mean ± standard error and graphed using GraphPad Prism 8 software.

[0142] 3 Results and analysis

[0143] 3.1 Single factor experimental results

[0144] (1) Raw material ratio

[0145] Fermentation greatly reduces the bitterness of the sunflower bee pollen raw material itself, and the pollen has a suitable sweet and sour taste, but still has a bitter aftertaste. Red dates are rich in bioactive compounds, such as polyphenols, flavonoids, polysaccharides and saponins, and have powerful antioxidant, antibacterial and anti-inflammatory biological activities. In addition to carbohydrates, jujube honey also contains proteins, enzymes, amino acids and organic acids, lipids, vitamins, minerals, flavonoids and phenolic compounds. Both red dates and jujube honey have natural sweetness, which can add sweetness to jam without the need to add too much other sweeteners, which meets the needs of healthy food. Figure 4It can be seen from A that when the fermented bee pollen: red dates: honey is 1:1:1, 2:1:1, and 2:2:1, the sensory score of the jam is good. Among them, when the ratio is 1:1:1, the sensory score is the highest, which is 75.55. At this time, the jam is brighter yellow, with sufficient floral and fruity aroma, delicate and smooth texture, and appropriate sweetness. When the ratio of each raw material is 3:1:1 and 4:2:1, the sensory score of the jam is not good, the aftertaste has the bitter taste of bee pollen, and the color is unpleasant brown-yellow. In summary, fermented bee pollen: red dates: honey is selected as 1:1:1, 2:1:1, and 2:2:1 for subsequent experiments.

[0146] (2) Xylitol addition amount

[0147] Xylitol is a sugar substitute widely used in the food and beverage industry. It has the advantages of low calories, good for dental health, and relatively little impact on blood sugar levels, so xylitol was chosen as a sweetener. Figure 4 It can be seen from Figure B that with the increase in the amount of xylitol added, the sensory score of the jam first increased and then decreased. When the amount of xylitol added was 3-10%, the sweetness of the jam was acceptable. When the amount of xylitol added was 15-20%, the product showed sugar precipitation after returning to room temperature, which seriously affected the quality of the jam. Therefore, the xylitol addition amounts of 5%, 7%, and 10% were selected for subsequent experiments.

[0148] (3) Amount of citric acid added

[0149] The raw materials of this product are fermented sunflower bee pollen, red dates, and jujube honey. Although fermented bee pollen can provide a slightly sour taste, the taste level is still too thin and needs to be improved, so citric acid is added to optimize the process. Figure 4 As shown in Figure C, when the citric acid addition amount was 0.1-0.3%, the sensory score of the jam showed an upward trend; when the citric acid addition amount was 0.3-0.5%, the sensory score of the jam showed a downward trend. Based on the comprehensive sensory score, the citric acid addition amount was 0.1%, 0.2%, and 0.3% for subsequent experiments.

[0150] (4) Vitamin A Addition

[0151] Depend on Figure 4 It can be seen from D that the sensory score of jam shows a trend of first increasing and then decreasing with the increase of vitamin A addition. Food-grade vitamin A is a light yellow powder with a slightly fishy smell. Low concentrations of vitamin A have little effect on the sensory organs of the product, but when the vitamin A addition reaches 0.4%, the jam will taste bitter and have a slightly greasy smell. Therefore, the vitamin A addition levels of 0.1%, 0.2%, and 0.3% were selected for subsequent experiments.

[0152] (5) Pectin addition amount

[0153] Pectin, as a polysaccharide compound, can increase the viscosity of pectin by forming a gel network, giving the jam good gel properties. Figure 4 It can be seen from E that with the increase of pectin addition, the sensory score of the jam shows a trend of first increasing and then decreasing. When the pectin addition is 0.1% and 0.4%, the texture of the jam is thin and easy to flow, and there is a phenomenon of solid-liquid separation. When the pectin addition is 0.6%, the sensory score of the jam peaks at 81.75, and then the sensory score begins to decline. When the pectin addition is 1.0%, the jam gels too quickly during the production process, and clumps appear, resulting in uneven texture of the jam. In addition, the viscosity of the jam is too high, and the stickiness is too strong, which causes the sensory score to drop rapidly. In summary, the optimal pectin addition is 0.6%.

[0154] 3.2 Orthogonal experimental results

[0155] The experimental results are shown in Table 12. From the R value, it can be seen that the order of influence of the four factors on the sensory score of the product is xylitol addition > citric acid addition > bee pollen: red dates: jujube honey ratio > vitamin A addition. According to the range analysis, the optimal process condition is A 2 B 2 C 2 D 1 According to Table 13, the ratio of bee pollen: red dates: jujube honey, the amount of xylitol added and the amount of citric acid added all have a significant effect on the sensory score of the product (p < 0.05), but the amount of vitamin A added has no significant effect on the sensory score of the product (p > 0.05). Considering the nutrition and sensory aspects of the product, A is selected. 2 B 2 C 2 D 2 As the best preparation plan for the product, the ratio of bee pollen: red dates: jujube honey is 2:1:1 (the total raw materials account for 46.25%), xylitol is added in an amount of 7%, citric acid is added in an amount of 0.3%, vitamin A is added in an amount of 0.2%, and pectin is added in an amount of 0.6%. At this time, the jam tastes sweet and sour, has a floral and fruity aroma, has a delicate texture, and can be evenly coated when applied.

[0156] Table 12 Results of orthogonal test of bee pollen jam

[0157]

[0158] Table 13 Variance results of orthogonal test of bee pollen jam

[0159]

[0160]

[0161] 3.3 Physical and chemical indicators of bee pollen jam

[0162] The indicators of the finished bee pollen jam are shown in Tables 14, 15 and 16. As shown in Table 14, the L* value of the bee pollen jam is 21.51, the a* value is 14.68, and the b* value is 46.62. The texture results of the finished product can be seen from Table 15. At this time, the texture of the bee pollen jam is delicate and uniform, with weak fluidity and good adhesion, and can easily form a uniform coating. As shown in Table 16, the moisture content of the finished product is 49.49%, the soluble solids are 41.33%, and the total sugar is 32.21%. At the same time, no total colony count and mold were detected in the finished product, indicating that the jam produced under the conditions meets the relevant national standards.

[0163] Table 14 Bee pollen jam color value determination results

[0164]

[0165] Table 15 Texture results of bee pollen jam under TPA mode

[0166]

[0167] Table 16 Physical and chemical indicators and microbiological indicators of bee pollen jam

[0168]

[0169] Note: “-” means not detected.

[0170] The present invention uses fermented bee pollen, red dates and honey (jujube honey) as raw materials, xylitol, citric acid, vitamin A and pectin as auxiliary materials, and uses a single factor combined with an orthogonal experiment to determine the optimal preparation method conditions of the bee pollen jam: fermented bee pollen: red dates: honey ratio 2:1:1 (the total raw material ratio is 46.25%), xylitol addition amount 7%, citric acid addition amount 0.3%, vitamin A addition amount 0.2%. Pectin addition amount 0.6%. At this time, the L* value of the jam is 21.51, the a* value is 14.68, the b* value is 46.62, the water content is 49.49%, the soluble solids are 41.33%, the total sugar is 32.21%, and the total number of colonies and mold are not detected. The jam under the optimal preparation conditions has a sweet and sour taste, a floral and fruity aroma, and a delicate texture.

[0171] In summary, the present invention develops a bee pollen jam with added vitamin A, which has a sweet and sour taste, a floral and fruity aroma, and a delicate texture. It is of great significance for developing bee pollen jam, enriching the variety of bee pollen products, and promoting the healthy development of the bee industry.

[0172] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing sunflower honeysuckle jam, characterized in that: The following steps are involved: Pretreated sunflower bee pollen, red dates and honey are mixed, and purified water is added to make pulp to obtain slurry; xylitol, citric acid and vitamin A are added, and pectin is added during heating and concentration until the soluble solid content is 40%-43%; the sunflower bee pollen jam is obtained.

2. The preparation method according to claim 1, characterized in that: The pretreatment includes inoculating composite lactic acid bacteria into the sunflower bee pollen for fermentation, wherein the composite lactic acid bacteria accounts for 10% of the mass of the sunflower bee pollen.

3. The preparation method according to claim 2, characterized in that: The preparation method of the composite lactic acid bacteria comprises: compounding Lactobacillus plantarum and Lactobacillus casei in a volume ratio of 3:

1.

4. The preparation method according to claim 2, characterized in that: The fermentation was carried out at 37°C for 72 hours.

5. The preparation method according to claim 1, characterized in that: The sunflower bee pollen, red dates and honey are mixed in a mass ratio of 2:1:

1.

6. The preparation method according to claim 1, characterized in that: The added amount of xylitol is 7% of the mass of the slurry; the added amount of citric acid is 0.3% of the mass of the slurry; the added amount of vitamin A is 0.2% of the mass of the slurry; and the added amount of pectin is 0.6% of the mass of the slurry.

7. The preparation method according to claim 1, characterized in that: The soluble solid content is 41.33%.

8. Sunflower bee balm jam prepared according to the preparation method according to any one of claims 1 to 7.

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