Method for producing an enriched vegetable oil for frying carbohydrate-rich foods

Abstract

The present invention relates to a method for producing an enriched vegetable oil comprising the preparation of a freeze-dried β-cyclodextrin additive, which is added to a vegetable oil, such as virgin olive oil or sunflower oil, in order to produce the enriched vegetable oil. Advantageously, using the enriched vegetable oil to fry carbohydrate-rich foods at temperatures between 175°C and 190°C reduces the concentration of acrylamide present in the fried food by at least 57% compared with the acrylamide produced in frying processes using unenriched vegetable oils.

Description

[0001] QUALIFICATION

[0002] Procedure for obtaining an enriched vegetable oil from frying carbohydrate-rich foods

[0003] DESCRIPTION

[0004] Procedure for obtaining an enriched vegetable oil from frying carbohydrate-rich foods

[0005] FIELD OF INVENTION

[0006] The present invention relates to a process for obtaining a vegetable oil enriched with a p-cyclodextrin-based additive, which can be used as a vegetable oil for frying carbohydrate-rich foods, and which, advantageously, allows the reduction of acrylamide concentration in fried foods, such as French fries, compared to the acrylamide concentration in foods fried with known oils.

[0007] PRIOR ART

[0008] Acrylamide (2-propenamide, C3H5NO, CAS 79-06-01) is a neurotoxic and genotoxic organic molecule for humans, classified since 1994 by the International Agency for Research on Cancer (IARC) in group 2A, as a probable carcinogen for humans based on studies carried out in animals [World Health Organization, “IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Some Industrial Chemicals”, 60, (1994)].

[0009] In 2002, the World Health Organization (WHO) registered acrylamide as a new food toxicant after a study conducted by the Swedish National Food Administration (SNFA) and researchers from Stockholm University demonstrated that carbohydrate-rich foods exhibit high levels of acrylamide when subjected to heat treatment above 120°C and low humidity [E. Tareke et al., “Analysis of acrylamide; a carcinogen formed in heated foodstuffs”, Journal of Agricultural and Food Chemistry, 50 (17), 4998-5006, (2002)]. Also in 2002, it was shown that acrylamide could be naturally generated from food components such as amino acids and reducing sugars, such as asparagine, during heat treatment as a result of the Maillard reaction [DS. Mottram et al., “Acrylamide is formed in the Maillard reaction", Nature, 419, 448-449, (2002)].

[0010] The Maillard reaction, also known as the non-enzymatic browning reaction, was discovered in 1912 by Louis Camille Maillard and is a process that occurs in both food and living organisms. This reaction constitutes the main pathway for acrylamide formation in food and is related to lipid oxidation, since both processes share common polymerization mechanisms, forming similar reaction byproducts [LC. Maillard, “Action of amino acids on sugars. Formation of melanoidins in a methodical way”, Comptes Rendus-Académie des Sciences, 154, 66-68, (1912)].

[0011] Acrylamide is found in foods such as cooked potato products, biscuits, cereals, bread, pastries, nuts, coffee, infant dairy products, fruits and vegetables, meat products, and fish [“Acrylamide in Food: Analysis, Content and Potential Health Effects. (Second Edition)”, V. Gokrnen and B. Atag Mogol (eds.), Academic Press, 1-618, (2023); AM Khaneghah et al., “The Concentration of Acrylamide in Different Food Products: A Global Systematic Review, Meta-Analysis, and Meta-Regression”, Food Reviews International, 38(6), 1286-1304, (2022)].

[0012] Due to scientific evidence on the effects of acrylamide consumption by humans, as well as the wide variety of foods containing this molecule, international authorities such as the Food and Agriculture Organization of the United Nations (FAO), the European Food Safety Authority (EFSA) of the European Union, and the Food and Drug Administration (FDA) of the United States government, as well as the European Commission and the Spanish Agency for Food Safety and Nutrition (AESAN) of the Government of Spain, have approved different recommendations, assessments, and regulations to reduce the concentration of acrylamide in products, which are mandatory for all economic operators [Official Journal of the European Union,“Regulation (EU) 2017 / 2158: Mitigation measures and reference levels for reducing the presence of acrylamide in food”, (2017); Center for Food Safety and Applied Nutrition, Food and Drug Administration, “FDA-2013-D-0715: Guidance for Industry Acrylamide in Foods”, (2016); Food and Agriculture Organization, “CAC / RCP 67-2009. Code of Practice for the Reduction of Acrylamide in Foods”, (2009)]. Since the relationship between acrylamide formation and the cooking process of carbohydrate-rich foods was demonstrated in 2002, several studies have been carried out with the aim of reducing the concentration of acrylamide present. It is important to note that FoodDrinkEurope regularly compiles the various methodologies developed in this field in the Acrylamide Toolbox [FoodDrinkEurope, “Acrylamide Toolbox 2019”, 1-64, (2019)]. Of particular note are the methods developed to reduce the amount of acrylamide in potato chips.in any of its forms.

[0013] Mitigation strategies for acrylamide formation in potatoes are based on the study of different potato varieties, type of cut (shape and thickness), optimization of humidity and temperature storage conditions, cooking method (pan, conventional or air fryer, oven and microwave), type of oil (olive, virgin olive, extra virgin olive, high oleic, linseed, rapeseed, sunflower, sesame, mixtures, among others), cooking time, application of additives to raw potatoes and post-cooking treatments [ES2673634; JP2005261397; W02017056096; ES2336784; JS. Elmore et al., “Effects of sulphur nutrition during potato cultivation on the formation of acrylamide and aroma compounds during cooking”, Food Chemistry, 122 (3), 753-760, (2010); RJ. Root et al., “Acrylamide in fried and roasted potato products: A review on progress in mitigation”, Food Additives & Contaminants: Part A, 24, 37-46, (2007); Y. Yuan et al., “Impact of selected additives on acrylamide formation in asparagine / sugar Maillard model systems", Food Research International, 44 (1), 449-455, (2011); FoodDrinkEurope, “Acrylamide Toolbox 2019", 1-64, (2019)].

[0014] Another strategy that has been developed on an industrial scale is the implementation of different stages of pretreatments involving washing (also called bleaching) and fermentation with synthetic and natural additives such as antioxidants, plant extracts, phenolic compounds, enzymes, probiotics, amino acids, divalent and trivalent acids and cations, and microbiological methods, with the aim of reducing the acrylamide content in potatoes [US20040058045A1; US20040109926A1 ; W02006099798; ES2336784; JP2005278448; MXPA / A / 2005 / 005391; MXPA / A / 2006 / 000181 ; ES2335500; MX2022009063; N. Khorshidian et al., “Using probiotics for mitigation of acrylamide in food products: a mini review”, Current Opinion in Food Science, 32, 67-75, (2020); E. Rottmann et al., “Enzymatic acrylamide mitigation in French fries -An industrial-scale case study”, Food Control, 123, 107739, (2021); ACE. Albedwawi et al., An overview of microbial mitigation strategies for acrylamide: Lactic acidbacteria, yeast, and cell-free extracts", LWT, 143, 111159, (2021)].

[0015] Furthermore, and due to the high level of technological development, techniques such as ultrasonic waves before a bleaching stage and subsequent vacuum frying (CN110037263), ionizing radiation to potatoes before cooking [X. Fan et al., “Effectiveness of ionizing radiation in reducing furan and acrylamide levels in foods”, Journal of Agricultural and Food Chemistry, 54 (21), 8266-8270, (2006); V. Gokrnen et al., “Effects of controlled atmosphere storage and low-dose irradiation of potato tuber components affecting acrylamide and color formations upon frying”, European Food Research and Technology, 224 (6), 681-687, (2007)] and a pre-treatment stage of freezing and defrosting potatoes by microwave [Y. Yuan et al., “Study of the methods for reducing the acrylamide content in potato slices after microwaving and frying processes”, RSC Advances, 4 (2), 1004-1009, (2014)].

[0016] However, although significant reductions have been achieved, the industrial application of these methods and technologies described has some drawbacks for producers:

[0017] - The potato variety cannot be kept stable for a whole year, so manufacturers select potatoes from different origins, with different compositions of reducing sugars, even if the variety is maintained.

[0018] - Maintaining sharp cutting blades.

[0019] - The chemical properties of each type of oil mean that the methods applied are not effective for everyone.

[0020] - The variation in cooking temperature (decrease) and time (increase) has caused an increase in production costs due to higher energy consumption, without managing to maintain the same properties in the potatoes.

[0021] - Loss of up to 20-25% of production due to the decrease in cooking temperature.

[0022] - Procedures based on a washing stage cause the potatoes to soften and, therefore, modify the organoleptic properties of the products.

[0023] - Procedures based on the addition of additives to potatoes cause the modification of organoleptic properties of the products and, therefore, the rejection by consumers.

[0024] - Increased production costs due to the reagents used in the washing or bleaching stages.

[0025] - High economic cost of techniques based on ionizing radiation and microwaves, as well as the difficulty in scaling up these technologies.

[0026] - No reduction in acrylamide concentration is achieved that complies with the new recommendations and / or legislation by public bodies.

[0027] Therefore, we can say that the main method to reduce the concentration of acrylamide corresponds to a bleaching process with a high economic cost and a loss of the organoleptic parameters and quality of the final product.

[0028] One of the alternative technologies with the greatest potential, although little used in the reduction of acrylamide concentration, is the encapsulation of compounds using extrinsic cyclodes as a host or guest molecule.

[0029] Cyclodextrins are natural compounds formed from naturally occurring cyclic oligosaccharides composed of 6, 7, and 8 glucose units (α-, β-, and γ-CD, respectively). These units form inclusion complexes with various hydrophobic host molecules, thereby improving the solubility and stability of these compounds. The application of cyclodextrins in the food industry began in 1970 with the discovery of their ability to retain volatile compounds that affected food flavor, and their use is now widespread globally.Examples of industrial-level use include: protection of bioactive compounds against oxidation and pro-oxidant mechanisms such as light-induced reactions, thermal decomposition, and loss of volatiles in certain foods; reduction and elimination of unwanted flavors and odors, as well as contaminants, increasing product shelf life; enrichment of vitamins with a high percentage of encapsulated antioxidant compounds in juices; improvement of the sensory parameters of food by solubilizing bitter and unpleasant substances for the consumer, as well as hydrophobic substances rich in fatty acids; and stabilization of fragrances, vitamins, and essential oils against physicochemical changes [JM. López-Nicolás et al., “Cyclodextrins and antioxidants”, Critical Reviews in Food Science and Nutrition, 54 (2), 251-256, (2014); A. Matencio et al., “Applications of cyclodextrins in food science.A review”, Trends in Food Science & Technology, 104, 132-143, (2020); Y. Kumar et al., “Food applications of cyclodextrins”, Sustainable Agriculture Reviews, 55, 201-238, (2021); A. González-Pereira et al., “Main applications of cyclodextrins in the food industry as the compounds of choice to form host-guest complexes”, International Journal of Molecular Sciences, 22 (3), 1339, (2021); A. Cid-Samamed et al., “Cyclodextrins inclusion complex: Preparation methods, analytical techniques and food industry applications”, Food Chemistry, 384 (1), 132-467, (2022)]. More recently, in addition to the above, developments have focused on the field of encapsulation of compounds (functional ingredients, metals, with antimicrobial, antiseptic or antioxidant activity) for the improvement of packaging of products [G. Astray et al., “A review on the use of cyclodextrins in foods", Food Hydrocolloids, 23 (7), 1631-1640, (2009); C. Rannou et al., “Mitigation strategies of acrylamide, furans, heterocyclic amines and browning during the Maillard reaction in foods", Food Research International, 90, 154-176, (2016)].

[0030] Debido a esta gran aplicabilidad, desde 1998, están admitidas como “Generalmente reconocido como seguro” (GRAS, por sus siglas en inglés) en la lista de aditivos alimentarios de la FDA permitidos para uso alimentario [Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, “Agency Response Letter Gras notice GRN No. 155", Silver Spring, MD, (2004); Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, “Agency Response Letter Gras notice GRN No. 74”, Silver Spring, MD, (2001); Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, “Agency Response Letter Gras notice GRN No. 46”, Silver Spring, MD, (2000)].In Europe, the three parental cyclodextrins (a-, - and y-) are registered in the Codex Alimentarius of the Joint FAO / WHO Expert Committee on Food Additives with the International Numbering System (INS) E-457, E-459 and E-458, respectively [Joint FAO / WHO Expert Committee on Food Additives, “Evaluation of certain food additives: sixty-third report of the Joint FAO / WHO Expert Committee on Food Additives”, 1-156 (2004)].

[0031] In three studies found in the state of the art, the use of cyclodextrins as a host molecule or cavity to mitigate acrylamide formation in carbohydrates has been investigated [W02004080205A1; AJ. Pérez-López et al., “Acrylamide content in French fries prepared with vegetable oils enriched with / 3-cyclodextrin or / 3-cyclodextrin-carvacrol complexes”, LWT, 148, 111765, (2021); M. Barón-Yusty et al., “Encapsulated EVOO improves food safety and shelf life of refrigerated pre-cooked chicken nuggets”, Clean Technology, 4 (1), 53-66, (2022)].

[0032] In the first piece of evidence, W02004080205A1, the inventors add alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, combinations thereof, and modified derivatives thereof in the preparation of food products and intermediate food products to reduce acrylamide levels. This is because the amino acid asparagine is sequestered in the hydrophobic binding pocket of the cyclodextrin, preventing it from reacting with a reducing end. In other words, they use cyclodextrins as a food additive before the cooking process (boiling, baking, and frying).

[0033] This same treatment is carried out in the third evidence by Barón-Yusty et al., where they encapsulated extra virgin olive oil in alpha-cyclodextrins and added them to the breading product of chicken pieces, prior to the ultra-freezing stage and subsequent frying [“Encapsulated EVOO improves food safety and shelflife of refrigerated pre-cooked chicken nuggets”, Clean Technology, 4 (1), 53-66, (2022)].

[0034] In the second piece of evidence (article by AJ. Pérez-López et al.), the addition of a pure, untreated p-cyclodextrin additive to the frying oil is disclosed, among other options, obtaining a reduction in the acrylamide content in the fried potatoes with the added oil of 15%.

[0035] For the reasons stated above, the lack of studies carried out with food products rich in carbohydrates or oils enriched with extrinsic cycloheximide compounds in real situations means that this and other methods of acrylamide reduction currently lack a globally known industrial application.

[0036] EXPLANATION OF THE INVENTION

[0037] The present invention relates to a process for obtaining a vegetable oil, such as sunflower oil or extra virgin olive oil, enriched with p-cyclodextrins for the reduction of acrylamide concentration in the cooking of carbohydrate-rich foods, such as frying potatoes.

[0038] The oil obtained by the process of the invention results in a significant improvement over the state of the art, since it solves the problems described above and makes it possible to reduce the concentration of acrylamide produced, among others, in the cooking of potato chips or fries, in a pan or fryer, applicable to restaurants and industrial plants.

[0039] For this purpose, a vegetable oil is added with a p-cyclodextrin additive synthesized by freeze-drying.

[0040] Thus, according to the essence of the invention, the procedure detailed below allows obtaining an enriched vegetable oil that includes at least freeze-dried p-cyclodextrins at a concentration of 1 g / L such that in the frying of carbohydrate-rich foods at temperatures between 175°C and 190°C, preferably for a minimum of 2 minutes, the concentration of acrylamide present in the fried food is reduced by at least 57% compared to the acrylamide produced in frying processes with conventional non-enriched vegetable oils.

[0041] Specifically, the manufacturing process for enriched vegetable oil comprises the following stages:

[0042] Preparation of a solution of p-cyclodextrins with water under stirring conditions. For this purpose, in one embodiment, 10.206 g of p-cyclodextrins are dissolved with 30 mL of distilled water using magnetic stirring; vacuum filtration of the solution prepared in the previous step, obtaining a filtrate and a solid residue;

[0043] freezing the filtrate obtained in the previous stage at at least -80°C for at least 24 hours;

[0044] dehydration by lyophilization at a temperature of at least -45°C and under vacuum pressure for at least three days, obtaining a lyophilized p-cyclodextrin additive; and

[0045] Agitation of a vegetable oil with the freeze-dried p-cyclodextrin additive obtained in the previous step to obtain an enriched vegetable oil, where the concentration of the additive in the enriched vegetable oil is 1 g of additive per liter of vegetable oil. Preferably, this step of adding the additive to enrich the vegetable oil is carried out with a propeller agitator at 1200 W, for 5 minutes.

[0046] The main advantages of this method of obtaining enriched vegetable oil are the following:

[0047] Its low economic cost and ease of industrial scaling.

[0048] It can be applied to any vegetable oil, so it is not exclusive to one type of oil.

[0049] The homogenization method is very simple, already commercially available, and does not require highly qualified personnel to obtain the enriched frying oil.

[0050] The enriched oils retain their physicochemical properties. BRIEF DESCRIPTION OF THE FIGURES

[0051] To complement the description being made and in order to help a better understanding of the characteristics of the invention, a set of figures is included as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented:

[0052] Figure 1.- Shows a schematic of the synthesis method of the additive called UACD-1 (lyophilized P-cyclodextrins) of the enriched vegetable oil of the invention.

[0053] Figure 2 shows a schematic of the process of adding / enriching a vegetable oil with the synthesized additive, followed by homogenization. The enriched vegetable oil (AV-UACD-1) is shown at the end.

[0054] Figure 3.- Shows the morphology and surface determined by scanning electron microscopy (SEM) with magnifications of x250 (top row) and x5000 (bottom row) for the additive UACD-1.

[0055] Figure 4 shows a thermogravimetric analysis (TGA) and its derivative (DTG) illustrating the mass loss with temperature for the additive UACD-1. The data series represent: (solid line) mass loss with temperature and (dashed line) the first derivative of the mass loss with temperature. The x-axis represents temperature in °C, the left y-axis mass in mg, and the right y-axis DTG in mg / s.

[0056] Figure 5.- Shows a differential scanning calorimetry (DSC) for the additive UACD-1, where the temperature in °C is represented on the abscissa axis and the heat flow in mW is represented on the ordinate axis.

[0057] Figure 6.- Shows the morphology and surface determined by scanning electron microscopy (SEM) with magnifications of 600 for an unaltered p-cyclodextrin additive, as disclosed in the article by AJ. Pérez-López et al. cited in the background section.

[0058] Figure 7.- Shows the particle size distribution of unaltered p-cyclodextrins, where the diameter (nm) is represented on the abscissa axis and the volume (%). on the ordinate axis

[0059] Figure 8.- Shows the thermogravimetric analysis (TGA) diagrams (Figure 8.A) and its derivative (DTG) (Figure 8.B) for CD-GO (inclusion complex formed by p-cyclodextrin and garlic oil), unprocessed p-cyclodextrin powder, recrystallized p-cyclodextrin and powder of the complex formed by garlic oil and p-cyclodextrin physically mixed, where the temperature in °C is represented on the abscissa axis and the weight loss in (%) on the ordinate axis

[0060] Figure 9.- Shows the DSC thermograms of p-cyclodextrin, red pepper extract, the complex formed by a physical mixture between the red pepper extract and the p-cyclodextrins, the complex between red pepper extract and the p-cyclodextrins formed by ultrasonic homogenization, and the complex of red pepper extract and the p-cyclodextrins formed by magnetic stirring, where the temperature in °C is represented on the abscissa axis and the heat flow (W / g) on ​​the ordinate axis.

[0061] DETAILED EXPOSURE OF MODES OF REALIZATION

[0062] Based on the configuration examples shown in the figures, specific, non-limiting ways of realizing the configuration will be described.

[0063] The procedure for cooking french fries includes the following variables: type of cooking, potato variety, type of oil, type of cut, temperature and cooking time.

[0064] Example 1

[0065] To demonstrate the advantages of the vegetable oil obtained according to an embodiment of the present invention, 500 mL of commercial virgin olive oil are placed in a 26 cm forged aluminum frying pan and heated on an induction hob to 180°C. Once the operating temperature is reached, 50 g of commercial frozen potatoes are added and fried for 3 minutes. The excess oil is then removed with absorbent paper.

[0066] The same procedure is followed for the enriched vegetable oil of the present invention. First, the oil is prepared by homogenizing 0.5 g of additive (UACD-1) with 500 mL of virgin olive oil, as shown in Figure 2. The final concentration was 1 g of additive / 1 L of oil. Then, the oil is individually fried at 180°C for 3 minutes.

[0067] The quantification of acrylamide concentration in potato chips was performed using high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD), following an extraction step. The extraction step consisted of placing 4 g of crushed and homogenized potato chips into a centrifuge tube with 20 mL of ultrapure water, vortexing for 10 minutes, and centrifuging for 15 minutes at 4500 rpm. Finally, the samples were filtered into a vial using a 0.45 µm PTFE filter. The HPLC conditions were as follows: C18 column, mobile phase composed of a 0.1% aqueous solution of formic acid (A) and acetonitrile (B) with a constant gradient of A = 99% and B = 1%, injected volume of 60 pL, flow rate of 0.7 mL / min, constant column temperature of 25°C, and a detection wavelength of 210 nm. The calibration curve is performed using a pure acrylamide standard.

[0068] Based on the data shown in Table 1 of the frying experiment with the enriched vegetable oil proposed in the present invention, it can be concluded that a partial reduction of acrylamide concentration is achieved in frozen french fries cooked for 3 minutes. Following this example, the additive consisting of freeze-dried p-cyclodextrins can be considered highly effective, with a reduction of 97.2%.

[0069] TABLE 1

[0070] Variation of acrylamide concentration for virgin olive vegetable oil enriched to a concentration of 1 g / L with additive synthesized from a freeze-drying process (AV-UACD-1: p-cyclodextrins), for a frying time of 3 minutes.

[0071] Sample Area [Acrylamide] (g / kg) % Reduction AV 88.3327 615.14

[0072] AV-UACD-1 6,1458 17,08 97,2

[0073] Example 2

[0074] In a second practical embodiment of the present invention, 500 mL of commercial virgin olive oil are placed in a 26 cm forged aluminum frying pan and heated on an induction hob to 180°C. Once the working temperature is reached, 50 g of commercial frozen potatoes are added and fried for 5 minutes. The excess oil is then removed with absorbent paper.

[0075] The same procedure is followed with the enriched vegetable oil that is the subject of this invention. First, the oil is prepared by homogenizing 0.5 g of additive (UACD-1) with 500 mL of virgin olive oil, as shown in Figure 2. The final concentration was 1 g of additive / 1 L of oil. Then, the oil is individually fried at 180°C for 5 minutes.

[0076] The quantification of acrylamide concentration in potato chips was performed using high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD), following an extraction step. The extraction step consisted of placing 4 g of crushed and homogenized potato chips into a centrifuge tube with 20 mL of ultrapure water, vortexing for 10 minutes, and centrifuging for 15 minutes at 4500 rpm. Finally, the samples were filtered into a vial using a 0.45 µm PTFE filter. The HPLC conditions were as follows: C18 column, mobile phase composed of a 0.1% aqueous solution of formic acid (A) and acetonitrile (B) with a constant gradient of A = 99% and B = 1%, injected volume of 60 pL, flow rate of 0.7 mL / min, constant column temperature of 25°C, and a detection wavelength of 210 nm. The calibration curve is performed using a pure acrylamide standard.

[0077] Based on the data shown in Table 2 of the frying experiment with the oil proposed in this invention, it can be concluded that there is a considerable increase in the concentration of acrylamide in the fried potatoes and that a partial reduction of the same is achieved in ultra-frozen fried potatoes cooked for 5 minutes, reaching a reduction of 57.8%.

[0078] TABLE 2

[0079] Variation of acrylamide concentration for virgin olive vegetable oil enriched to a concentration of 1 g / L with additive synthesized from a freeze-drying process (AV-UACD-1: p-cyclodextrins), for a frying time of 5 minutes.

[0080] Sample Area [Acrylamide] (pg / kg) % Reduction AV 260.9607 1523.46

[0081] AV-UACD-1 117,1495 642,95 57,8It is also worth noting that the procedure of the present invention allows obtaining an enriched vegetable oil that not only offers the possibility of reducing the production of acrylamide in the frying of food by up to a percentage close to 100% compared to the acrylamide produced with unenriched vegetable oil, but also offers improved results in frying processes with other enriched vegetable oils.

[0082] In this regard, the article by AJ. Pérez-López et al. cited above describes a frying experiment conducted with virgin olive oil enriched with pure p-cyclodextrins, that is, unaltered p-cyclodextrin powder. This experiment was carried out at 180°C for 4 minutes, resulting in a 15% reduction in acrylamide concentration compared to the acrylamide produced in a frying process using virgin olive oil without additives.

[0083] Comparing this result and extrapolating it to the data shown in Tables 1 and 2, it can be concluded that the vegetable oil enriched with the freeze-dried p-cyclodextrins obtained by the procedure of the present invention offers a significantly greater reduction in acrylamide content than the oil enriched with non-freeze-dried p-cyclodextrins.

[0084] The following details information relating to the characterization of the lyophilized p-cyclodextrin particles used as an additive for the enrichment of vegetable oil according to the essence of the present invention, in order to illustrate the advantages of the format of the additive used.

[0085] To achieve this, the additive is synthesized according to the following steps:

[0086] - Dissolving 10.206 g of p-cyclodextrins in 30 mL of distilled water by stirring;

[0087] - Freezing the solution prepared in the previous step at at least -80°C for at least 24 hours;

[0088] - Dehydration by freeze-drying at a temperature of at least -45°C and vacuum pressure for at least three days, obtaining an additive.

[0089] Following the synthesis of the additive, a characterization is performed to determine the influence of the drying method on properties such as particle size, zeta potential, morphology, and thermal stability. Analysis of particle size and zeta potential using dynamic light scattering (DLS).

[0090] First, it's important to note that a large particle size results in lower physical stability, solubility, and bioavailability. Smaller particles tend to remain in suspension longer, making them more stable and improving the overall stability of the formulation.

[0091] Regarding the zeta potential, it's important to note that it's a measure of the surface electrical charge of particles in a suspension and provides relevant information for understanding the suspension's stability. A high zeta potential indicates greater electrostatic repulsion between particles, which generally leads to greater colloidal stability.

[0092] As can be seen in Table 3, the additive called UACD-1 of freeze-dried p-cyclodextrins prepared according to the object of the present invention has a particle size of 419 nm, which could indicate good solubility in frying oil, since, being a particle size less than 600 nm, it would already have nanomaterial properties, and therefore, good solubility.

[0093] Regarding the zeta potential, it is worth noting that it is a negative potential of -52.8 mV, which indicates good colloidal stability due to the electrostatic repulsion between the particles.

[0094] TABLE 3

[0095] Particle size and Z potential of the UACD-1 additive of lyophilized p-cyclodextrins prepared according to the object of the present invention vs unaltered p-cyclodextrins.

[0096] Sample Particle size (nm) Zeta potential (mV) UACD-1 419 -52.8 unaltered P-cyclodextrins 644 -24.0

[0097] Comparing the particle size values ​​of the lyophilized p-cyclodextrins of the present invention with the unaltered p-cyclodextrins used as an additive to vegetable oils employed in the reduction of acrylamide concentration (article by AJ. Pérez-López et al.), the following information has been found in the literature reflected in Figure 7 (J. He et al., “Investigating the oxyresveratrol / 3-cyclodextrin and 2-hydroxypropyl- / 3-cyclodextrin complexes: The effects on oxyresveratrol solution, stability, and antibrowning ability on fresh grape juice” LWT 100, 263-270, 2019), where it is observed that the particle size distribution of p-cyclodextrins shows a mean diameter of 644 nm, so the narrower particle size distribution and smaller particle size obtained with the procedure of the invention can be attributed to the inclusion preparation process, which includes dissolving the p-cyclodextrins by magnetic stirring, vacuum filtration, freezing, and lyophilization drying at low temperature and high pressure.

[0098] Regarding the zeta potential values, it is worth highlighting those published (LM. Mendes Gomes et al., “Inclusion complexes of red bell pepper pigments with γ-cyclodextrin: Preparation, characterisation and application as natural colorant in yogurt’ Food Chemistry, 148, 428-436, 2014) for unaltered and unmodified p-cyclodextrin, which was -24.0 mV. In this case, compared with the UACD-1 additive, the value was higher, indicating poorer colloidal stability due to electrostatic repulsion between the particles.

[0099] Analysis of surface morphology and distribution using scanning electron microscopy (SEM).

[0100] Figure 3 shows the surface area determined by scanning electron microscopy at magnifications of 250x (top row) and 5000x (bottom row) for the UACD-1 additive. As can be seen, the UACD-1 sample exhibits small, uniform particles without significant aggregation, which is expected for free p-cyclodextrins. The fact that this UACD-1 additive does not exhibit significant aggregation and its particles are small (preferably less than 600 nm) and uniform offers several advantages, such as greater stability in suspension, which prevents sedimentation and flocculation—an important characteristic for a homogeneous and effective formulation. Free p-cyclodextrins do not aggregate until they reach their site of action. It is also worth noting that uniform, non-aggregated particles have more consistent physicochemical properties, such as a higher specific surface area and better solubility, compared to aggregated particles.Finally, it should be noted that the absence of aggregation facilitates the handling and processing of nanoparticles, simplifying the production and scaling up of possible formulations.

[0101] Figures 6 (LM. Mendes Gomes et al., “Inclusion complexes of red bell pepper pigments with α3-cyclodextrin: Preparation, characterisation and application as natural colorant in yogurt” Food Chemistry, 148, 428-436, 2014) and 7 (S. Li et al., “Characterization of garlic oil / α-cyclodextrin inclusion complexes and application” Food Chemistry Volume 10, 2023) show SEM microscopy images analogous to that of Figure 3. In Figure 6, the α-cyclodextrins stand out due to their irregular crystal morphology that forms blocks, in addition to having a particle size larger than that of the UACD-1 additive.

[0102] Thermal stability analysis by thermogravimetric analysis (TGA / DTG) with differential scanning calorimetry (DSC).

[0103] To complete the characterization of the additive that includes the enriched vegetable oil of the invention, Figures 4 and 5 show the data obtained for the analysis of thermal stability by thermogravimetric analysis (TGA) and its derivative (DTG) with differential scanning calorimetry (DSC).

[0104] Regarding TGA and DTG analysis, it is a technique in which the mass change of a sample is measured during heating or cooling to determine its thermal decomposition or reaction characteristics. Its derivative provides a better graphical visualization of these mass changes in the material.

[0105] Regarding differential scanning calorimetry (DSC) analysis, it is a technique in which the heat difference requires an increase in the temperature of the sample and the reference is measured as a function of the temperature, providing information on whether an exothermic or endothermic process is occurring.

[0106] As can be seen in the thermogravimetric analysis with differential scanning calorimetry shown in Figures 4 and 5, the UACD-1 additive offers excellent thermal stability, as no endothermic peaks were observed. Furthermore, it should be noted that in the frying process operating range (160-190°C), the UACD-1 additive shows no mass loss or variations in heat flow, again indicating its high thermal stability.

[0107] To compare the results obtained for the TGA / DTG of lyophilized p-cyclodextrin (UACD-1) versus unprocessed p-cyclodextrin powder, Figure 8 is included (S. Li et al., “Characterization of garlic oil / fi-cyclodextrin inclusion complexes and application” Food Chemistry Volume 10, 2023), where Figure 8.A shows the TG graphs for four different materials: CD-GO (inclusion complex formed by p-cyclodextrin and garlic oil), unprocessed p-cyclodextrin powder, recrystallized p-cyclodextrin, and powder of the inclusion complex formed by garlic oil and p-cyclodextrin by physical mixing.

[0108] In this case, before the first stage at 110°C, 13.1% of the weight is lost due to the evaporation of water from inside the p-cyclodextrin cavity, while the UACD-1 additive loses 11.7%. The reason for the lower weight loss of the freeze-dried additive compared to the pure one is that, due to the drying process at -80°C and high pressure, the water molecules inside the cyclodextrin cavity were able to evaporate from the surface of the cyclodextrin material.

[0109] Regarding the results shown for the first-order derivative of the TG, a graph of the DTG variation is obtained in Figure 8.B. The DTG graph allows for a closer look at the thermal effects of the different materials. It is worth noting that the UACD-1 additive exhibits a maximum mass loss peak at 320°C, while the maximum DTG peak shown for unprocessed p-cyclodextrin was approximately 305°C. Therefore, the synthesis procedure for the additive of the present invention demonstrates a clear improvement in its stability.

[0110] Another comparison of the DSC analysis of p-cyclodextrin is presented in Figure 9 (LM. Mendes Gomes et al., “Inclusion complexes of red bell pepper pigments with γ-cyclodextrin: Preparation, characterisation and application as natural colorant in yogurt,” Food Chemistry, 148, 428–436, 2014). In this case, the DSC of pure p-cyclodextrin shows a broad thermal peak between 115°C and 160°C, with a maximum around 140°C, which may be related to degradation. Additionally, a thermal spike near 300°C is also observed, which is generally attributed to the onset of p-cyclodextrin decomposition.Comparing these results with those obtained for UACD-1, it is worth highlighting the earlier first thermal peak associated with mass loss due to water, and the slight thermal increase to 310°C, so the lyophilized p-cyclodextrin obtained by the procedure of the present invention has better stability to thermal decomposition.

Claims

CLAIMS 1 a - Manufacturing process for an enriched vegetable oil comprising the following steps: - preparation of a solution of p-cyclodextrins with water under agitated conditions; - vacuum filtration of the solution prepared in the previous stage, obtaining a filtrate and a solid residue; - freezing of the filtrate at at least -80°C for at least 24 hours; - dehydration by freeze-drying at a temperature of at least -45°C and under vacuum pressure for at least three days, obtaining a freeze-dried p-cyclodextrin additive; and - agitation of a vegetable oil with the freeze-dried p-cyclodextrin additive obtained in the previous stage to obtain an enriched vegetable oil, wherein the concentration of the additive in the enriched vegetable oil is 1 g of additive per liter of vegetable oil; Thus, when using enriched vegetable oil for frying carbohydrate-rich foods at temperatures between 175°C and 190°C, the concentration of acrylamide present in the fried food is reduced by at least 57% compared to the acrylamide produced in frying processes with non-enriched vegetable oils. 2 a - Manufacturing process of the enriched vegetable oil according to claim 1 a , characterized in that the p-cyclodextrin solution includes 10.206 g of p-cyclodextrins dissolved in 30 mL of distilled water. 3 a - Manufacturing process of the enriched vegetable oil according to claim 1 a , characterized in that the agitation of the vegetable oil with the additive is carried out with a propeller agitator at 1200 W for 5 minutes.

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