Development of a novel cryostructured composite coating of xanthan-bovine collagen-oregano essential oil spraying applied for the preservation of commercial biscuits marketed in Mexico.

Cryostructured gels, better known as cryogels, are a very important emerging class of biomaterials that have diverse applications in food preservation. This work shows a novel alternative to prepare a cryostructured composite coating made from a blend of xanthan, bovine collagen, and oregano essential oil. The composite coating was suitably applied onto the surface of preservative-free biscuits which were stored for 15 days at 25 ± 2°C and 52% ± 1% relative humidity. The evaluation focused mainly on the changes in the physicochemical, textural, and microbiological characteristics of the biscuits. It was found that the coated samples significantly (p < 0.05) decreased moisture absorption, water activity, and fungal growth. However, the composite coating minimally impacted the quality of biscuits in terms of color, texture profile, and surface microstructure. Overall, the cryostructured composite coating constitutes an advance in technological strategies aimed at the preservation of baked products. This will allow, in the future, the development of novel coatings on bakery products to generate new trends in the conservation of their properties and extension of shelf life. This could be achieved through the implementation of new technologies in the food industry, with the aim of making them more environmentally friendly and contributing to the generation of less plastic waste. PRACTICAL APPLICATION: The study and application of cryogels, as innovative systems in the food industry, allow to expand and diversify the materials that can function as coatings to maintain some quality characteristics, in this case in bakery products, so it is important to analyze their effects and consider them to improve conservation processes.

Comparative study of conventional frying and air frying on the quality of potatoes (Solanum tuberosum L.).

The human being has historically consumed fried foods for centuries; however, conventional frying has a disadvantage, immersion in vegetable and/or animal oils, which leads to the search for different options. This is why air frying is a good alternative, which still has a wide field of study. In this work, frozen French fries of a brand marketed in Mexico that were subjected to frying in canola oil and air frying were compared. They were evaluated through the change in the removed moisture content, water activity, color profile, hardness, fracturability, and surface damage by SEM, thermal analysis by MDSC, and chemical by FTIR-ATR spectroscopy. Air-fried French fries were found to contain about 48% less moisture, fewer perceptible color changes, and less surface damage translated into better crunchiness compared with conventionally fried. It was also found that the changes at the chemical level are smaller, mainly attributed to the absence of canola oil and that the thermal transitions are more stable in terms of temperatures and enthalpies, which makes it possible to emphasize that air frying is a good alternative for developing new fried products that allow expanding the variety of these in the market without sacrificing some quality attributes.

Effect of Cryostructuring Treatment on Some Properties of Xanthan and Karaya Cryogels for Food Applications.

Cryogels are novel materials because the manufacturing process known as cryostructuring allows biopolymers to change their properties as a result of repeated controlled freeze-thaw cycles. Hydrogels of xanthan and karaya gums were evaluated after undergoing up to four controlled freeze-thaw cycles in indirect contact with liquid nitrogen (up to -150 °C) to form cryogels. Changes in structural, molecular, rheological, and thermal properties were evaluated and compared to those of their respective hydrogels. Samples were also analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Rotational Rheology (RR), Modulated Differential Scanning Calorimetry (MDSC) and zeta potential (ζ). In general, significant differences (p < 0.05) between the numbers of freeze-thaw cycles were found. Karaya cryogels were not stable to repeated cycles of cryostructuring such as the three-cycle xanthan cryogel, which has the best structural order (95.55%), molecular interactions, and thermal stability, which allows the generation of a novel material with improved thermal and structural properties that can be used as an alternative in food preservation.

Effect of Starter Culture and Low Concentrations of Sodium Nitrite on Fatty Acids, Color, and Escherichia coli Behavior during Salami Processing.

The reduction of NaNO2 and safety in meat products have been a concern to the meat industry for the last years. This research evaluated the changes in total fatty acids (TFAs) and myoglobin forms by adding starter culture (Lactobacillus sakei/Staphylococcus carnosus) and 50 ppm of NaNO2 during salami processing. In the postripening stage, the starter culture influenced the concentration of the palmitic, oleic, vaccenic, and γ-linolenic TFAs, whereas the metmyoglobin concentration was lower (which could be related to the antioxidant effect of the starter culture). In this stage, an increase in enthalpy, specific heat, and onset temperature was found when adding starter culture and NaNO2, which is directly related to polyunsaturated TFA. However, when adding just the starter culture without 50 ppm NaNO2, the E. coli population was reduced in 4 log CFU/g. This study proposes the analysis of changes in meat product processing like salami in a holistic form, where the application of starter culture with low nitrite concentrations could be in the meat industry an upward trend for reducing this additive.

Thermal, Structural, and Rheological Characterization of Waxy Starch as a Cryogel for Its Application in Food Processing.

Starch is the major component of cereal, pulses, and root crops. Starch consists of two kinds of glucose polymers, amylose and amylopectin. Waxy starch-with 99⁻100% amylopectin-has distinctive properties, which define its functionality in many food applications. In this research, a novel material was prepared through the cryogelification of waxy starch (WS) using four cycles of freezing and thawing in indirect contact with liquid nitrogen at -150 °C. Polyvinyl alcohol (PVA) was used as a reference. The cryogels were characterized using several validation methodologies: modulated differential scanning calorimetry (MDSC), scanning electron microscopy (SEM), rheology, and Fourier transform infrared (FTIR) spectroscopy with diffuse reflectance (DR). Based on the number of freeze⁻thaw cycles, significant changes were found (P < 0.05) showing important structural modifications as well as reorganization of the polymeric matrix. Two cryogelification cycles of the WS were enough to obtain the best structural and functional characteristics, similar to those of PVA, which has already been tested as a cryogel. From these results, it is concluded that WS has potential as a cryogel for application in food processing.

Liver exhibits thermal variations according to the stage of fibrosis progression: A novel use of modulated-differential scanning calorimetry for research in hepatology.

AIM: Liver fibrosis results in a disproportion of the hepatic composition and architecture, characterized by a progressive accumulation of fibrillar proteins at the liver parenchyma. Modulated-differential scanning calorimetry (mDSC) is an experimental methodology able to determine the specific thermal signature from any biological substance, based on the variation in heat flow and heat capacity. As these physicochemical properties are directly influenced by compositional and structural changes, we decided to study the thermal behavior of the liver during fibrosis using mDSC. METHODS: Liver fibrosis was induced in rats by bile duct ligation or carbon tetrachloride administration. Degree of liver fibrosis was determined by histological examination using the Masson-trichrome stain, accompanied by hepatic expression of α-smooth muscle actin. The thermal analysis was performed in a modulated-differential scanning calorimeter using 20 mg of fresh liver mass. RESULTS: The liver showed a characteristic thermal signature in control animals, which progressively differed among mild (F1), moderate (F2) and advanced (F3-F4) liver fibrosis. For heat flow, the hepatic thermal signature from F3-F4 rats exhibited significant differences when compared with F1, F2 and controls. In terms of heat capacity, liver specimens provided a specific thermal signature for each stage of disease, characterized by a transition temperature onset at 95°C for controls, whereas in F1, F2 and F3-F4 animals this temperature significantly decreased to 93°C, 84°C and 75°C, respectively. CONCLUSION: Because the liver shows a differential thermal signature according to the degree of fibrosis, mDSC could be a novel tool in the study of liver fibrosis progression.