RESUMEN
Although thermal treatments are beneficial for the preservation and safety of milk, they can also alter its immunogenic activity by affecting its protein components. To achieve precise results, it is essential to identify the specific proteins that cause food allergies. Therefore, investigating the possible alterations of cow's milk proteins (CMPs) resulting from thermal treatments is necessary. In this study, the Fourier transform infrared spectroscopy (FTIR) technique was used to analyze the effect of UHT thermal treatment on the secondary structures of milk casein. Using the second derivative, six characteristic peaks were identified in the Amide I region, ranging from 1700 to 1600 cm-1. It was found that thermal treatments produce shifts in absorption peaks, indicating changes in protein conformation and possibly in allergenic activity. These shifts were clearly identified in the first characteristic peak of samples M8 and M9, from 1621 to 1600 cm-1. The results suggest that thermal treatments may promote protein aggregation by increasing ß turns and reducing ß sheets and α helices, which could enhance the allergenic potential of the proteins and facilitate the formation of complexes between different milk proteins, such as ß-lactoglobulin and κ-casein. Further studies are needed to experimentally validate the allergenic activity of proteins modified by thermal treatments, as only an analytical method (FTIR) was used to evaluate the secondary structures of the proteins.
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Spray-drying is a commonly used method for producing powdered flavors, but the high temperatures involved often result in the loss of volatile molecules. To address this issue, our study focused on a novel approach: developing O/W Pickering emulsions with agri-food byproducts to encapsulate and protect D-limonene during spray-drying and storage. Emulsions formulated with lupin hull, lupin-byproduct (a water-insoluble protein-fiber byproduct derived from the production of lupin protein isolate), and camelina press-cake were subjected to spray-drying at 160 °C. The results revealed that these emulsions exhibited good stability against creaming. The characteristics of the dry emulsions (powders) were influenced by the concentration of byproducts. Quantitative analysis revealed that Pickering emulsions enhanced the retention of D-limonene during spray-drying, with the highest retention achieved using 3% lupin hull and 1% camelina press-cake. Notably, lupin-stabilized emulsions yielded powders with enhanced oxidative stability compared to those stabilized with camelina press-cake. Our findings highlight the potential of food-grade Pickering emulsions to improve the stability of volatile flavors during both processing and storage.
RESUMEN
Natural Pickering emulsions are gaining popularity in several industrial fields, especially in the food industry and plant-based alternative sector. Therefore, the objective of this study was to characterize and compare six agri-food wastes/byproducts (lupin hull, canola press-cake, lupin byproduct, camelina press-cake, linseed hull, and linseed press-cake) as potential sources of food-grade Pickering stabilizers. The results showed that all samples contained surface-active agents such as proteins (46.71-17.90 g/100 g) and dietary fiber (67.10-38.58 g/100 g). Canola press-cake, camelina press-cake, and linseed hull exhibited the highest concentrations of polyphenols: 2891, 2549, and 1672 mg GAE/100 g sample, respectively. Moreover, the agri-food byproduct particles presented a partial wettability with a water contact angle (WCA) between 77.5 and 42.2 degrees, and they were effective for stabilizing oil-in-water (O/W) emulsions. The emulsions stabilized by Camelina press-cake, lupin hull, and lupin by-product (≥3.5%, w/w) were highly stable against creaming during 45 days of storage. Furthermore, polarized and confocal microscopy revealed that the particles were anchored to the interfaces of oil droplets, which is a demonstration of the formation of a Pickering emulsion stabilized by solid particles. These results suggest that agri-food wastes/byproducts are good emulsifiers that can be applied to produce stable Pickering emulsions.
RESUMEN
There is an increasing interest in consuming healthy foods motivated by the need of boosting the immune system naturally. In this sense, vegetables rich in bioactive compounds are a clear example of "superfoods" that promotes overall health and strengthen the immune response. Therefore, in this study eight traditional vegetables usually produced in southern Chile (pea, corn, carrot, leek, spinach, chard, coriander and parsley) were characterized in terms of their nutritional composition to evaluate their potential as lyophilized natural ingredients. Thus, chemical composition, amino acid profile, minerals, vitamins, carotenoids, polyphenols and pesticide residues were evaluated. Green leafy vegetables resulted to be an excellent source of proteins and dietary fibers as well as vitamins (ascorbic acid, choline, alpha-tocopherol and niacin), minerals (calcium, phosphorus and iron), carotenoids and polyphenols. Among the eight vegetables assessed spinach exhibited the more balanced nutritional profile. Moreover, 332 pesticide residues were analysed and only six were detected in a low concentration. Due to their nutritional properties, the present results suggest that vegetables produced in southern Chile could be considered as promising alternatives to develop natural food ingredients.
Asunto(s)
Carotenoides , Verduras , Ácido Ascórbico , Chile , Valor NutritivoRESUMEN
Chitin is one of the most abundant natural polysaccharides in the world and it is mainly used to produce chitosan by a deacetylation process. In the present study, the extraction of chitin and chitosan from the Parastacus pugnax (P. pugnax) crayfish exoskeleton was studied for the first time. Thus, the P. pugnax crayfish exoskeleton was converted to chitosan following the steps of depigmentation, deproteinization, and deacetylation. The produced chitosan (Chitosan-CGNA) was characterized in terms of the protein content, solubility, degree of deacetylation, viscosity, molecular weight, FTIR, SEM, XRD, antimicrobial, and antioxidant activity. The results showed that the obtained chitosan had a high degree of deacetylation (91.55%) and a medium molecular weight (589.43 kDa). The antibacterial activity of the chitosan was tested against bacterial strains relevant for the food industry and the lowest minimum inhibitory concentration (MIC) values were evidenced with Salmonella tiphymurium (S. typhimurium), Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis) and Listeria. Monocytogenes (L. monocytogenes). Moreover, the Chitosan-CGNA showed an effect on DPPH radical scavenging activity, and its antioxidant activity was dependent on concentration and deacetylation degree. These results suggest that P. pugnax exoskeleton could be an excellent natural source for the production of chitosan with potential applications in the health system, and to prevent infections associated with pathogens strains.
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In recent years, interest in plant-based proteins has been rising due to ethical and sustainability issues. In this context, the production of protein concentrates and isolates from new plant sources have increased enormously because of their nutritional and techno-functional properties. Therefore, this work describes a pilot process for obtaining protein-rich ingredients from a yellow lupin variety (Lupinus luteus) developed by the Agriaquaculture Nutritional Genomic Center (CGNA). A protein alkaline solubilisation followed by isoelectric precipitation was used as a method for obtaining a protein concentrate (LPC) and isolate (LPI) with 75 and 95% protein, respectively. The changes in the protein quality and chemical composition during the protein concentration process from lupin flour were evaluated. Thus, nutritional parameters such as the amino acids (AAs) profile, essential amino acid index (EAAI), chemical score (CS), the protein efficiency ratio (PER), and digestible indispensable amino acid score (DIAAS) were determined to evaluate the nutritional quality of LPC and LPI. The facile and scalable protein isolation method without a defatting process proposed in this study showed a great protein separation efficiency (PSE), while the amino acids profile was not affected during both the concentration as well as the isolation of proteins. In addition, SDS-PAGE showed that both LPC and LPI mainly contained the high-molecular-weight proteins α and ß-conglutins. Both LPC and LPI had a balanced amino acids profile, and arginine was the most predominant amino acid. These results are useful for increasing the use of lupin based-protein ingredients as a potential functional ingredient in the food industry.