Tempeh chips with improved acid value stability and their manufacturing method

Abstract

The method for producing tempeh chips with improved acid value stability and rancidity resistance involves frying tempeh made from black-eyed peas in coconut oil. Tempeh chips produced in this way exhibit a stable acid value and can meet acid value standards and requirements for import and export while maintaining their unique nutritional value and flavor.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority based on Korean Application No. 10-2023-0023174, filed on February 21, 2023, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present disclosure relates to a method for producing tempeh chips, and more particularly to a method for producing tempeh chips with a more stable acid value by using cowpeas (black-eyed peas) and coconut oil. [Background technology]

[0003] Tempeh (or tempe) is a traditional fermented soybean food originating in Indonesia. Tempeh is generally produced by boiling and peeling soybeans, inoculating them with a strain of Rhizopus fungus, and fermenting them. Tempeh is a fermented soybean food and is a nutritious food containing abundant protein, probiotics, dietary fiber, vitamins, and minerals. Furthermore, tempeh can be eaten in a variety of ways, such as by cutting it into small pieces and frying or stir-frying, making it an easy-to-eat vegan food. In recent years, coupled with various health-conscious consumer trends, it has become an internationally popular food.

[0004] However, many countries have set strict acid value standards for imported foods, such as fried snacks, to ensure the safety of imported foods on the market. Tempeh chips, which are made from soybeans by deep-frying tempeh to create a savory snack, often do not meet the acid value index standard of 2.0 mg KOH / g FFA. This makes it difficult to import and export these tempeh chips.

[0005] The use of soybeans as an ingredient has the potential to cause oxidation during the frying process, resulting in higher than required acidity levels, due to soybeans' relatively high fat content.

[0006] Therefore, it is necessary to develop a method for producing tempeh chips that improves the stability of the acid value while maintaining the nutritional value of tempeh. Summary of the Invention

[0007] One aspect of the present disclosure provides tempeh chips with improved acid value stability, which stably maintains an acid value below the acid value standards of many countries and has an extended shelf life.

[0008] Another aspect of the present disclosure provides a method for producing such acid stability enhanced temp chips by formulation using cowpeas (black-eyed peas) cooked in coconut oil.

[0009] According to the present disclosure, a method for producing temp chips includes frying beans in coconut oil. The following features may be included singly or in any combination:

[0010] The frying step is carried out at about 150° C. to about 180° C. The frying step may be carried out for about 5 minutes to about 7 minutes. The acid value of the tempeh chips may be about 2.0 mg KOH / g FFA or less.

[0011] In some embodiments, the method may further include soaking the beans in water at about 60° C. to about 70° C. for about 3 to about 10 minutes prior to the frying step.

[0012] In some embodiments, the method may further comprise the step of germinating the beans. For example, germination may occur for about 24 to about 30 hours. During the germination process, root sprouts may grow to about 1 to 2 mm. The method may further comprise the step of removing the outer shell of the beans.

[0013] The method may further include soaking the dehulled beans in water with vinegar for about 15 to about 17 hours. The method may further include boiling the soaked beans in water for about 5 to about 15 minutes. The method may further include cooling the boiled beans, mixing the beans with tempeh mold (Rhizopus oligosporus), and storing the beans to prepare fermented tempeh.

[0014] In some embodiments, the storing step may include a first storing step at about 29°C to about 32°C for about 20 to about 25 hours, and a second storing step at about 28°C to about 30°C for about 7 to about 12 hours. During the second storing step, the internal temperature of the tempeh may be maintained at about 46°C to about 48°C.

[0015] The second storing step may include slicing the tempeh to a thickness of about 1.0 mm to about 1.5 mm. The moisture content of the sliced ​​tempeh may be about 44% or more, and the pH may be within the range of about 4.5 to about 6.0.

[0016] In some embodiments, the beans may include black-eyed peas.

[0017] Another aspect of the present disclosure includes tempeh chips produced by the methods described herein.

[0018] The manufacturing process for tempeh chips according to the present disclosure can preserve the nutritional value and unique flavor of tempeh. The manufactured tempeh chips have sustained acid value stability, allowing the product to be distributed for a longer period from the date of manufacture.

[0019] The advantages of the present disclosure are not limited to these, and other advantages can be understood from the following description. [Brief explanation of the drawings]

[0020] [Figure 1]Tempeh mixture during fermentation in the fermentation chamber. The tempeh mixture was placed in plastic bags (or tubes), clipped at both ends, and fermented at temperatures of 50°C, 48°C, and 45°C. [Figure 2] FIG. 1 shows tempeh chips made using cowpea (black-eyed pea) and coconut oil, which were stored in the first fermentation chamber for 24 hours and then fermented in the second fermentation chamber for an additional 8 hours. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present disclosure provides a method for producing tempeh chips with improved acid value stability by cooking black-eyed peas in coconut oil. By frying black-eyed peas in coconut oil, the tempeh chips of the present disclosure have excellent acid value stability and rancidity resistance while maintaining a nutty flavor and high nutritional value.

[0022] The cowpea beans used in this disclosure are best known in English as "black-eyed peas" due to the small black spot in the center of each bean. Throughout this disclosure, the phrase "black-eyed peas" is used interchangeably with "cowpea beans."

[0023] Black-eyed peas are characterized by their low calorie content, high protein and carbohydrate content, high iron and potassium content, sweet taste, and ease of digestion. These beans are often used as ingredients in dietary supplements and health foods that are popular among people of all ages. While black-eyed peas are generally known to be native to West Africa, they are now cultivated worldwide, including in the United States, India, and China. Cultivation of these beans is feasible in the Korean climate, and production primarily occurs between July and September under favorable climatic conditions.

[0024] Because black-eyed peas have a low fat content, the compositional properties of tempeh chips according to the present disclosure are advantageous in maintaining stable acid values.

[0025] Coconut oil as used in this disclosure is a type of vegetable oil extracted by drying and pressing the flesh of coconuts without adding any chemicals. Coconut oil is produced using coconuts harvested from Southeast Asia, India, South America, and Africa, where palm trees are widely cultivated.

[0026] While most vegetable oils are composed of unsaturated fatty acids, coconut oil is rich in saturated fatty acids and solidifies below room temperature.

[0027] The tempeh chips of the present disclosure can maintain a stable acid value and have a rich and unique taste due to the use of black-eyed peas and coconut oil.

[0028] In this disclosure, the process of frying (e.g., deep frying) tempeh prepared in coconut oil may refer to the process of submerging the food in oil and deep frying.

[0029] The frying process according to the present disclosure may be carried out while maintaining the temperature of the coconut oil in the range of about 130° C. to about 190° C. For example, the temperature of the coconut oil may be maintained at about 140° C. to about 190° C., about 150° C. to about 190° C., about 150° C. to about 180° C., about 150° C. to about 170° C., about 150° C. to about 160° C., about 160° C. to about 190° C., about 170° C. to about 190° C., about 175° C. to 190° C., about 180° C. to about 190° C., or about 185° C. to about 190° C.

[0030] In some embodiments, the frying step may be carried out at a temperature ranging from about 150° C. to about 160° C. Due to the nature of tempeh, the high fat content of the beans used as raw material tends to burn, so frying at a low temperature is desirable.

[0031] Furthermore, the frying time according to the present disclosure may be about 3 minutes to about 15 minutes. For example, the frying time may be about 3 minutes to about 10 minutes, about 3 minutes to about 7 minutes, about 5 minutes to about 15 minutes, about 5 minutes to about 10 minutes, about 5 minutes to about 7 minutes, about 7 minutes to about 15 minutes, about 7 minutes to about 10 minutes, or about 10 minutes to about 15 minutes. These frying times impart an excellent crispy texture and an appetizing golden color to the tempeh chips.

[0032] As used herein, the phrase "acid value stability" may refer to a state in which oxidation of oil and / or beans is suppressed or prevented during the tempeh manufacturing process, maintaining a more stable, low acid value. Tempeh chips with improved acid value stability prevent or minimize the occurrence of oxidation, prevent rancidity, and reduce health risks. Therefore, tempeh chips with improved acid value stability can be distributed with a longer shelf life from the date of manufacture due to their more stable acid value, which is lower than the maximum value required by importing countries.

[0033] As used herein, "acid value" may be defined as the amount of potassium hydroxide (KOH) in milligrams (mg) required to neutralize the free fatty acids (FFAs) in 1 g of a sample (i.e., mg of KOH per gram of FFA). This means that the FFA content is measured indirectly as the number of mg of potassium hydroxide required to neutralize it. Tempeh chips with improved acid value stability according to the present disclosure may have an acid value of 2.0 mg KOH / g FFA or less. For example, the acid value may be stably maintained at approximately 0.7 mg KOH / g FFA during transportation, distribution, and storage. Generally, all foods oxidize over time, so the acid value gradually increases over time after the food is prepared.

[0034] The tempeh chips with improved acid value stability of the present disclosure may further contain an antioxidant. An antioxidant is a substance that inhibits oxidation. Commonly used antioxidants include butylhydroxytoluene (BHT) and tocopherol, but the present disclosure is not limited thereto. The present disclosure may use either BHT or tocopherol.

[0035] In some embodiments, the method of the present disclosure may include soaking the black-eyed beans in water and removing the skins from the black-eyed beans prior to frying the black-eyed beans in coconut oil. The soaking of the black-eyed beans in water may be performed while maintaining the temperature of the water at about 50°C to about 80°C. For example, soaking may be performed at about 50°C to about 70°C, about 60°C to about 80°C, or about 60°C to about 70°C. Further, soaking may be performed for about 2 minutes to about 15 minutes. For example, soaking may be performed for about 2 minutes to about 13 minutes, about 2 minutes to about 10 minutes, about 3 minutes to about 15 minutes, about 3 minutes to about 13 minutes, or about 3 minutes to about 10 minutes. Soaking the black-eyed beans allows the skins to be more easily peeled without hardening or breaking.

[0036] In some embodiments, the disclosed method may include a step of sprouting black-eyed peas. Without being bound by any particular theory, the sprouting step may increase the protein content of tempeh. Traditional soybean tempeh generally contains about 6 g of protein per 50 g package. However, black-eyed pea tempeh may have a lower protein content than soybean tempeh depending on the type of bean. For example, black-eyed pea tempeh contains about 4 g of protein per 50 g package. To increase the protein content, black-eyed peas may be germinated before producing tempeh.

[0037] For example, black-eyed peas may be germinated for about 12 to about 48 hours. For example, germination may be carried out for about 18 to about 36 hours, about 24 to about 36 hours, or about 24 to about 30 hours. After the germination process, root sprouts (radicles) grow on the black-eyed peas. For example, 24 to about 30 hours after germination, the black-eyed peas grow root sprouts of about 1 mm to about 2 mm. By adding the germination process, the protein content of black-eyed pea tempeh increases to about 5.2 g per 50 g package.

[0038] The method of the present disclosure may further include soaking the peeled black-eyed peas in water with added vinegar. The soaking of the black-eyed peas in water with added vinegar may be carried out for, for example, about 12 to about 20 hours, about 12 to about 17 hours, about 15 to about 20 hours, or about 15 to about 17 hours. Soaking the peeled black-eyed peas in water with added vinegar promotes and accelerates fermentation in the production of tempeh.

[0039] The method of the present disclosure may further include a step of rinsing the black-eyed beans soaked in vinegar-added water and then boiling them in water. The boiling in water may be carried out for, for example, about 3 to about 20 minutes, such as about 3 to about 15 minutes, about 5 to about 20 minutes, or about 5 to about 15 minutes. Cooking the black-eyed beans in boiling water may remove unwanted microorganisms and moisture remaining on the surface of the black-eyed beans, thereby allowing fermentation to proceed more efficiently.

[0040] Fermented tempeh can be prepared by cooling boiled black-eyed peas, mixing them with bacterial strains, and storing them for a period of time. Bacterial strains that can be used for fermentation may include Rhizopus species, more specifically the tempeh fungus Rhizopus oligosporus.

[0041] In this process, starch may be mixed with the beans and bacterial strains. Starch is a polymeric carbohydrate consisting of many glucose units linked by glycosidic bonds. When mixed with water, starch produces a viscous paste that acts as a thickener, stiffener, or adhesive for foods. The starch used in the present disclosure may be extracted from the storage root of cassava, also known as tapioca starch.

[0042] The tempeh fermentation period may include a first (e.g., initial) storage step and a second (e.g., secondary) storage step. The first storage step may store the tempeh for about 20 to about 25 hours at about 29°C to about 32°C. For example, the first storage step is carried out for about 24 hours at about 29°C to about 32°C. The second storage step is carried out following the first storage step and is carried out at about 28°C to about 30°C for about 6 to about 12 hours. For example, the second storage step may be carried out for about 6 to about 12 hours, about 6 to about 10 hours, about 6 to about 8 hours, about 7 to about 12 hours, about 7 to about 10 hours, or about 7 to about 8 hours.

[0043] In the storage process of the present disclosure, the first and second storage steps can be combined for a period of about 29 to about 32 hours. If the storage period exceeds about 32 hours, the tempeh may be over-fermented, resulting in the development of an unpleasant odor and a loss of commercial value.

[0044] The method according to the present disclosure may further include a step of cutting (e.g., slicing) the tempeh to a thickness of about 1.0 mm to about 1.5 mm. The slicing step may be performed during the second storing step. The thickness of the tempeh is not limited to the above range, and any thickness that is suitable and / or convenient for consumption and optimal texture may be used.

[0045] In some embodiments, the slicing step may be performed during the second storage step before the 32 hour period, as slicing after the 32 hour period may increase the acidity of the tempeh.

[0046] The moisture content of sliced ​​tempeh may be about 44% or greater, and the pH may be in the range of about 4.5 to about 6.0. It is important to produce tempeh that meets these ranges, as even small variations in moisture content and / or pH can result in noticeable differences in the taste of tempeh chips.

[0047] The improved recipe according to the present disclosure can produce tempeh chips with improved acid value stability and resistance to rancidity through the above-described manufacturing process. Tempeh chips produced by the above-described manufacturing process retain the flavor and nutritional components of tempeh chips, have excellent resistance to rancidity, and can maintain a stable acid value below the standard value required by importing countries, allowing them to be distributed for a longer period from the date of manufacture.

[0048] A production example of tempeh chips according to the present disclosure will be described in detail below. Manufacturing Example 1: Manufacturing method of tempeh chips Preparation Example 1.1: Preparation of black-eyed peas In this preparation example, 1 kg of fresh black-eyed peas was prepared. The black-eyed peas should have dark brown skin and be free of wrinkles and pest contamination. The skins (e.g., husks, pods) of the black-eyed peas were removed before boiling. However, due to the small size of black-eyed peas, removing the skins can be difficult. Therefore, to easily and efficiently remove the skins, the black-eyed peas were soaked in water at a temperature of about 60°C to about 70°C for about 5 minutes. After soaking, the skins of the black-eyed peas were removed using a machine.

[0049] The dehulled black-eyed peas were boiled in water for approximately 40 minutes. Boiling after dehulling allows the black-eyed peas to maintain their round shape without being crushed or squashed. After boiling, the black-eyed peas were rinsed in cold running water at approximately 10°C to 20°C.

[0050] Then, vinegar was added to about 500 g of water to prepare a 3% vinegar solution. The washed beans were soaked in this vinegar solution for about 16 hours. The soaked black-eyed beans were then washed again with cold water.

[0051] The washed black-eyed beans were boiled again in water for about 10 minutes. Boiling the black-eyed beans removes any remaining moisture or microorganisms in the beans, potentially promoting the fermentation process more efficiently.

[0052] The boiled black-eyed peas were transferred to a tray lined with filter cloth to remove excess water and then cooled with a fan. During cooling, the beans' condition must be carefully monitored to avoid inactivating or killing the strain of tempeh bacteria required for fermentation.

[0053] Preparation Example 1.2: Preparation of tempeh mixture Two grams of tempeh bacteria strain and 1,000 grams of tapioca starch were mixed with 1.5 kg of cooled black-eyed peas. The strain was first mixed, and after thorough mixing, the tapioca starch was added to prepare the final mixture. The addition of tapioca starch can give tempeh chips a crispy texture.

[0054] Before starting the fermentation of the mixture, the moisture content of the mixture was checked to make sure it was at least 46%. The proper moisture content for tempeh is 46% or more so that it can ferment properly and not dry out and crumble when sliced.

[0055] The mixture was filled into a plastic bag with one or both ends open for fermentation. The ends of the bag were tied and secured with clips, and the mixture in the bag was stored in a first fermentation chamber at a temperature of about 29 to 31°C and a humidity of about 60 to 70% for 24 hours (first storage step).

[0056] After the first 24 hours in the first fermentation chamber, an additional fermentation of 6 to 8 hours was carried out in the second fermentation chamber, whose temperature was about 28°C to about 30°C and was adjusted based on the internal temperature of the tempeh mixture (second storage step).

[0057] If the internal temperature of tempeh exceeds 48°C, the tempeh may become overly acidic, for example, due to over-fermentation, and if the internal temperature falls below 46°C, the tempeh may crack or crumble when sliced. Adjustments were made depending on these conditions (Figure 1).

[0058] While the tempeh was fermenting during the second storage step, it was sliced ​​to a thickness of about 1.0 mm to about 1.5 mm using a slicer. Tempeh breaks easily and is more difficult to maintain its round shape when cut during the first storage step, and cutting tempeh after 32 hours of the second storage step may result in overfermentation.

[0059] After slicing, tempeh should have a moisture content of at least 44% and a pH between 4.5 and 6.0. Since even slight variations in moisture and pH can affect the success of fermentation, it is important to maintain these ranges to ensure a consistent taste for tempeh chips.

[0060] Preparation Example 1.3: Production of tempeh chips A solution of 1.08 g of BHT (an antioxidant) was added to 6 L of coconut oil (such as that available from Barco) to prevent the fat from going rancid. Additionally, a solution of 15 g of salt, 30 g of minced garlic, and 1500 L of water was prepared for soaking.

[0061] The sliced ​​tempeh was dipped in the soaking liquid, then removed and fried in coconut oil at approximately 150°C for approximately 5 to 7 minutes until crispy, and then cooled (Figure 2).

[0062] After the tempeh chips were cooled, the moisture content of the chips was measured to ensure it did not exceed 3%.

[0063] The tempeh chips were then mixed with seasoning powder and stirred thoroughly. The moisture content of the chips was confirmed to be no more than 2%. The tempeh chips were then packaged in aluminum packaging with an oxygen absorber (e.g., Oxymove®) and nitrogen.

[0064] Example 1. Acid value test of tempeh chips Example 1.1. Acid value test of tempeh chips prepared with soybean and coconut oil Tempeh chips were produced in a manner similar to that disclosed above, except that the tempeh chips were prepared by frying soybeans in coconut oil. Prior to packaging, the acid values ​​of various seasonings were measured.

[0065] [Table 1]

[0066] As shown in Table 1 above, all tempeh chips made using a combination of soybean and coconut oil exhibited high acid values, regardless of the type of seasoning used. Even without added seasoning, a high acid value of 7.10 mg KOH / g FFA was recorded after frying.

[0067] Example 1.2. Acid value test of tempeh chips made using soybeans and various oils Soybeans were prepared by frying them in coconut oil, palm oil, sunflower oil and rice bran oil, and the acid value of each was measured.

[0068] [Table 2]

[0069] As shown in the table above, soybean tempeh chips showed a higher acid value than all other types of oil, with no significant effect depending on the type of fat or antioxidant, or the oil blend ratio. On the other hand, when fried in 100% coconut oil, a lower FFA content was recorded than in the coconut and palm oil blend. This indicates that coconut oil helps maintain a stable acid value.

[0070] Example 1.3. Acid value test of tempeh chips made with black-eyed peas and coconut oil 4000 g of black-eyed peas, 3272 g of tapioca starch, and 2 to 3 g of tempeh bacteria were mixed and prepared according to the method described in Preparation Example 1 above.

[0071] The black-eyed peas were soaked for 11 hours and fermented for 31 hours. First, 6 L of coconut oil and 2.16 g of tocopherol were used to heat the coconut oil for 3 hours. In this example, a stable FFA content range was confirmed, as shown in Table 3 below.

[0072] [Table 3]

[0073] As mentioned above, an attempt was made to test whether a stable acid value would be maintained when coconut oil frying was carried out for a longer period of time using 6 L of coconut oil and 2.16 g of tocopherol.

[0074] As shown in Table 4, the FFA content increased after 6 hours of frying. After 6 hours of frying, 2 L of coconut oil and 0.72 g of tocopherol were added and the frying was continued for another hour, for a total of 7 hours of frying. The acid value obtained in this example remained stable at 1.31 mg KOH / g FFA.

[0075] [Table 4]

[0076] Even when tempeh chips made with black-eyed peas were fried in coconut oil for more than seven hours, the acid value remained low and stable.

[0077] As shown in Table 2, soybeans were fried in coconut oil, palm oil, sunflower oil, and rice bran oil, and the acid value was measured after 1 to 3 hours. High acid values ​​of 4.70 mg KOH / g FFA to 7.30 mg KOH / g FFA were recorded. On the other hand, as shown in Table 4, when black-eyed peas were fried in coconut oil, a low and stable acid value of 1.30 mg KOH / g FFA was recorded even after 6 to 7 hours.

[0078] The antioxidant effect of tocopherol compared to BHT was evaluated by measuring FFA content. As shown in Table 5 below, the FFA content increased after two hours of frying. After two hours, 1.5 L of coconut oil and 0.4 g of BHT were added. Additional coconut oil and BHT were added, and the FFAs were measured 4.5 hours after the initial frying step. In this example, the use of BHT as an antioxidant resulted in lower FFA values ​​than the use of tocopherol as an antioxidant, confirming superior acid value stability.

[0079] [Table 5]

[0080] Example 2. Sensory evaluation of black-eyed pea tempeh chips fried in coconut oil As shown in Table 6, the tempeh chips prepared according to the present disclosure did not have a rancid taste and provided a crispy texture, resulting in tempeh chips with more desirable properties.

[0081] [Table 6]

Claims

1. The process for making tempeh chips involves frying beans in coconut oil.

2. 10. The method of claim 1, wherein the frying step is carried out at about 150°C to about 180°C.

3. 10. The method of claim 1, wherein the frying step is carried out for about 5 to about 7 minutes.

4. 2. The method of claim 1, wherein the acid value of the tempeh chips is about 2.0 mg KOH / g FFA or less.

5. 10. The method of claim 1, further comprising the step of soaking the beans in water at about 60°C to about 70°C for about 3 to about 10 minutes prior to the frying step.

6. 6. The method of claim 5, further comprising the step of germinating the beans for about 24 to about 30 hours.

7. 7. The method of claim 6, further comprising removing the skins from the beans.

8. 8. The method of claim 7, further comprising soaking the dehulled beans in water with added vinegar for about 15 to about 17 hours.

9. 10. The method of claim 8, further comprising boiling the soaked beans in water for about 5 to about 15 minutes.

10. cooling the boiled beans; mixing the beans with a tempeh strain; and storing the beans to prepare fermented tempeh.

11. The storing step comprises: a first storage step at about 29°C to about 32°C for about 20 hours to about 25 hours; and a second storage step at about 28°C to about 30°C for about 7 hours to about 12 hours.

12. 12. The method of claim 11, wherein the internal temperature of the tempeh is maintained at about 46°C to about 48°C during the second storing step.

13. 12. The method of claim 11, wherein the second storing step comprises slicing the tempeh to a thickness of about 1.0 mm to about 1.5 mm.

14. 14. The method of claim 13, wherein the sliced ​​tempeh has a moisture content of about 44% or more and a pH within the range of about 4.5 to about 6.

0.

15. The method of claim 1 , wherein the beans comprise black-eyed peas.

16. Tempeh chips produced by the method of claim 1.

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