Utilization of gallic acid-crosslinked soy proteins as wall material for chia oil microencapsulation.

BACKGROUND: Chia oil represents the vegetable source with the highest content of omega-3 fatty acids. However, the incorporation of polyunsaturated fatty acids into food is limited due to their susceptibility toward oxidation. This investigation aimed to study the microencapsulation of chia oil (CO), using gallic acid (GA) crosslinked-soy protein isolate (SPI) as a wall material and its effect on its oxidative stability. RESULTS: Microcapsules presented a moisture content, water activity, and encapsulation efficiency of around 2.95-4.51% (wet basis); 0.17 and 59.76-71.65%, respectively. Rancimat tests showed that with higher GA content, the induction period increased up to 27.9 h. The storage test demonstrated that the microencapsulated oil with crosslinked wall material has lower values of hydroperoxides and higher induction times concerning the non-crosslinked oil. Finally, the fatty acid profile at this storage time indicated that microcapsules with GA did not have significant changes. In vitro digestion exhibited a reduction in the percentage of bioavailable oil for crosslinked microcapsules, but with no variations in its chemical quality, and an increase in the total polyphenols amount and antioxidant activity. CONCLUSION: The results obtained demonstrated that the microencapsulation of CO using SPI crosslinked with GA as wall material exerted a very important protective effect since a synergistic effect could be described between the microencapsulation effect and the antioxidant power of GA. © 2023 Society of Chemical Industry.

Porous Microparticles of Corn Starch as Bio-Carriers for Chia Oil.

Native corn starch and pretreated corn starch were treated with α-amylase, glucoamylase and mixtures of both to generate starches with high porosity with conserved granular structure. Porous starches were characterized; particle size distribution analysis, nitrogen adsorption-desorption analysis, scanning electron microscopy, water and oil adsorption capacity, differential scanning calorimeter, X-ray diffraction and damaged starch techniques were used. The α-amylase/glucoamylase mixture at the highest dose was the best treatment to generate porous starches with interesting adsorption capacity and granular structure conservation. Selected starches were impregnated with chia oil using a vacuum. Pretreated corn starch modified with the α-amylase/glucoamylase mixture showed no significant differences on impregnation capacity compared with native starch with a similar enzyme treatment. The highest oxidative stability was achieved with pretreated porous starch impregnated with 10 to 25% chia oil, compared with the bulk oil (5.37 to 4.72 and 2.58 h, respectively). Results have demonstrated that vacuum impregnation could be a potential technique for the incorporation of oil in porous structures based on starch and porous starches obtained by enzymatic hydrolysis are a promising material for the incorporation and protection of oils susceptible to oxidation.

Influence of the extraction conditions on chia oil quality and partially defatted flour antioxidant properties.

Partially defatted chia flour (PDCF) is a by-product of oil extraction from chia seeds (Salvia hispanica L.). It may be used as an ingredient to improve food products, especially due to its antioxidant properties. In this work, we studied the best screw press extraction conditions that allow preserving the antioxidant properties of PDCF. A central composite design was applied to perform a response surface analysis in order to optimize the oil extraction. The variables considered for optimization were seed moisture content and pressing temperature. Besides the oil quality indicators, the study was focused on the assessment of PDCF properties, including total polyphenol content and antioxidant capacity determined by chemical methods. Our results show that, within the range of screw press conditions evaluated, the chemical quality of the oil and the antioxidant properties of PDCF are both preserved. The best results (highest oil yield and stability) were obtained under a seed moisture content of 10.2% and a pressing temperature of 58.5 °C. In general, our results indicate that screw press methodology can be applied to process chia seeds, using a wide range of conditions, to concurrently produce good quality oil and a PDCF with beneficial properties.

Novel cookie formulation with defatted sesame flour: Evaluation of its technological and sensory properties. Changes in phenolic profile, antioxidant activity, and gut microbiota after simulated gastrointestinal digestion.

Defatted sesame flour (DSF), a coproduct of the sesame oil extraction process, is often discarded despite having high polyphenol content. The aim of this study was to improve the antioxidant properties of cookies with increasing amounts of DSF (5, 10, and 20%) and study its impact on processing and gastrointestinal digestion. Besides, we evaluated the effect of this incorporation on the technological and sensory properties of cookies. The formulation with 10% (SFC10) showed technological quality similar to control, and was the most accepted by consumers. After baking, 13 out of 25 polyphenols from DSF were observed, and only 19% of the initial SFC10 polyphenols would be potentially absorbed after digestion. Besides, the addition of DSF benefits the microbiota composition after colonic fermentation. In conclusion, supplementation with 10% of DSF in cookies improves sensorial acceptance and antioxidant properties, without affecting the technological ones.

Effects on bread and oil quality after functionalization with microencapsulated chia oil.

BACKGROUND: Omega-3 and omega-6 fatty acids-rich oils suffer oxidation reactions that alter their chemical and organoleptic quality. Microencapsulation can be a powerful tool for protection against ambient conditions. In the present study, the addition of microencapsulated chia oil as an ingredient in bread preparations and its effect on the technological and chemical quality of breads was investigated. RESULTS: Microencapsulation of chia oil was carried out by freeze-drying with soy proteins as wall material and oil release was determined under in vitro gastric and intestinal conditions. Encapsulated oil-containing bread showed no differences in specific volume, average cell area, firmness and chewiness with respect to control bread. Unencapsulated oil-containing bread showed a marked increase in hydroperoxide values respect to control, whereas encapsulated oil-containing bread values were not affected by baking and bread storage. The fatty acid profiles showed a decrease of 13% and 16%, respectively, in α-linolenic acid in the encapsulated and unencapsulated oils with respect to bulk chia oil. Sensory analysis showed no significant differences between bread samples. CONCLUSION: The addition of encapsulated chia oil did not alter the technological quality of breads and prevented the formation of hydroperoxide radicals. A ration of encapsulated oil-containing bread contributes 60% of the recommended dietary intake of omega-3 fatty acids. © 2018 Society of Chemical Industry.

Wheat germ stabilization by infrared radiation.

Wheat germ has an important enzymatic activity, being lipases the enzymes which cause the highest impact in the reduction of shelf life. The objective of this study was to evaluate the effects of infrared radiation on wheat germ stabilization in an attempt to extend the shelf life. The effects of treatment time, gap (sample distance to IR emitters) and infrared radiation intensity on wheat germ were analyzed through response surface methodology. Final moisture content, final temperature, color of germ and germ oil quality parameters: free fatty acid content changes and total tocopherol content were the responses evaluated using a Box-Behnken design. A combination of an infrared radiation intensity of 4800 W/m2, a 3 min treatment and 0.2 m emitter-sample distance were the best processing condition to stabilize the wheat germ without significantly reduction of the tocopherol content. A confirmatory experiment was conducted with these optimal conditions, and the heat-treated and raw germ samples were stored for 90 days at room temperature in three layer packages to protect them against light and oxygen. The oil quality parameters indicated that the raw germ had a shelf-life of about 15 days, with the heat-treated wheat germ maintaining its quality for at least 90 days under these stored conditions.

Optimization of soybean heat-treating using a fluidized bed dryer.

This study was designed to optimize drying and inactivation of heat-labile inhibitors conditions of soybean by using a fluidized bed dryer, in order to shorten treatment time and to reduce losses in end-product quality such as soy flour color and soy protein solubility. The independent variables were initial moisture of soybeans, heating time and temperature of air entering the fluidization chamber. The response variables studied were final moisture of soybeans, inactivation of urease, soy flour color and soy protein solubility. Response surface methodology was able to model the response of the different studied variables. For each response group, relevant terms were included into an equation; the behavior of response was predicted within the experimental area and was presented as a response surface. The results suggested that a combination of soybean initial moisture of 0.14 g/g (wb), treatment time of 3.4 min and hot-air temperature of 136.5 °C could be a good processing combination of parameters for heating soybean using hot-air in order to reduce treatment time and quality losses in soybean flour. Thus, fluidized bed drying technology may be used as an alternative industrial method to eliminate the antinutritional factors.

Walnut (Juglans regia L.): genetic resources, chemistry, by-products.

Walnut (Juglans regia L.) is the most widespread tree nut in the world. There is a great diversity of genotypes differing in forestry, productivity, physical and chemical nut traits. Some of them have been evaluated as promising and may serve as germplasm sources for breeding. The nutritional importance of the nut is related to the seed (kernel). It is a nutrient-dense food mainly owing to its oil content (up to 740 g kg(-1) in some commercial varieties), which can be extracted easily by screw pressing and consumed without refining. Walnut oil composition is dominated largely by unsaturated fatty acids (mainly linoleic together with lesser amounts of oleic and linolenic acids). Minor components of walnut oil include tocopherols, phospholipids, sphingolipids, sterols, hydrocarbons and volatile compounds. Phenolic compounds, present at high levels in the seed coat but poorly extracted with the oil, have been extensively characterised and found to possess strong antioxidant properties. The oil extraction residue is rich in proteins (unusually high in arginine, glutamic and aspartic acids) and has been employed in the formulation of various functional food products. This review describes current scientific knowledge concerning walnut genetic resources and composition as well as by-product obtainment and characteristics.