Adolfo Armando Rayas-Amor

Objective: To assess the effect of popping thermal treatment on the physical and structural properties of Toluqueño creole popcorn maize (Zea mays L.) Design/methodology/approach: Toluqueño creole maize and commercial (Zea mays L.), as a control, were subjected to three popping treatments: hot oil, hot air and microwave. Moisture, popping yield, textural properties (hardness, gumminess, chewing), and structural features (size: area, perimeter) by image analysis were determined. Results: The results showed that the treatment by hot air in commercial maize presented the best pop yield, reaching a value of 71.88%, while the microwave treatment was the best for Toluqueño maize, with 12.93% of expansion yield, because its low moisture content (8.42 ± 0.29%). The best textural characteristics for both types of maize were obtained after applying the hot air treatment, resulting in soft, low rubbing and good chewing for all samples. The microstructural analysis in Toluqueño maize treated by microwave evidenced the presence of spherical starch granules, which was attributed to a low gelatinization degree. Also was possible to observe highest intergranular space, which was related to a less compactation grade and consequently less hardness in the raw grain (without expansion). Limitations on study/implications: High resolution and improved methodologies to observe the starch grain and components distribution could be result in a better description of the effect of thermal treatment in the maize grains. Findings/conclusions: The treatment by hot air was the best process to obtain popcorn for all samples, being the commercial maize who presented the best physical and structural features.

Feeding is an elementary human need from which we obtain the energy and nutrients necessary for development and survival. Health heavily depends on food, which can be a means of different microbial hazards when contaminated at any stage of the food chain, compromising food safety and consumer health. Fish are considered widely produced foods (fishing or aquaculture) and are marketed worldwide; they are also a basic element of the human diet because they are a source of proteins and lipids. On the other hand, owing to their chemical properties (neutral pH and water activity), fish are highly susceptible to contamination by saprophytic and pathogenic microorganisms related to spoilage and risk to human health. Among the contaminating microorganisms in fish are bacteria of the genus Klebsiella, which are considered important in human and animal health worldwide due to their opportunistic pathogenicity, resistance to various antimicrobials, and association with numerous infections at the community and hospital levels, where foods such as fish and other products can serve as important sources of transmission. Therefore, this document presents a bibliographic review focused on describing, in a general way, the genus Klebsiella and its relationship with human health, aquatic animal health, and the safety of fish and products, as well as laboratory analysis procedures and identification of control and prevention measures of this biological hazard in fish and products to safeguard public health.

Fish is a food that is widely produced, marketed, and consumed around the world. It is a basic component of human nutrition due to its chemical and nutritional composition, but at the same time is highly perishable and susceptible to contamination throughout the food chain, compromising its quality and safety. Fishing and aquaculture products, being perishable, require adequate processing and preservation to maintain their quality and safety as much as possible until their acquisition and final consumption. Different preservation methods have been developed and used to extend the shelf life of fish products with minimal impact on their nutritional and organoleptic properties. Therefore, the objective of this document is to provide, through the search, analysis, and selection of information from various databases such as Scopus, Scielo, Web of Science, and Google Scholar, among others, a general and basic informative description of fish, aimed at academics, producers, industrialists, and the general public that allows them to identify the basic points in the processing and preservation of the quality and safety of fish. Aspects related to production; the nutritional qualities of fish; the various physical, chemical, and biological contaminating hazards of fish; the control and prevention of contaminants and diseases for consumers; and food legislation for products are included, as well as the main traditional and modern methods applied in the preservation of fishery and aquaculture products to maintain their nutritional value, quality, and safety that allow for the availability of food and the protection of public health.

Objective: Evaluate the effect of the substitution of cow milk with soy beverage on the antioxidant properties, physicochemical parameters, and sensory quality of the probiotic and conventional fermented beverages. Design/methodology/approach: Different combinations of soy beverage (T1=80%, T2=60%, T3=40%, and T4=20%) with cow milk (20%, 40%, 60%, and 80%, respectively) were fermented with either conventional or probiotic cultures. The antioxidant activity of fermented beverages was evaluated by DPPH method and the samples were also characterized for protein, fat, solids non-fat, density, and acidity. Sensory evaluation was done in order to determine the acceptability of the fermented beverages. Results: Overall, most treatments fermented with the probiotic culture showed higher (PStudy Limitations: Follow-up research is needed to identify the bioactive compounds responsible for antioxidant properties exhibited by fermented soy-dairy milk beverages. Findings/conclusions: Probiotic cultures can be used to generate soy- dairy milk fermented beverages with noticeable antioxidant and sensory properties.

The objective was to assess the in vitro rumen fermentation characteristics, methane production, and biohydrogenation of unsaturated fatty acids of diets with two protected fat (PF) sources from soybean or linseed oil, two levels of PF (0 and 6%) and two forage sources (canola silage (CS) or alfalfa hay (AH)) in a factorial 2x2x2 completely randomised design. Only fatty acids content at final incubation was affected (PP0.05). Gas production and in vitro NDF digestibility were lower with 6% PF of linseed than soybean (160.88 vs 150.97 ml; and 69.28vs 62.89 %, respectively PP<0.05) but IVDMD had the opposite result (78.54 vs 85.04). In conclusion, although methane production was not affected and in vitro digestibility and gas production were reduced with linseed PF, the concentration of C18:3 and C18:1 trans-11 was increased, which could improve the lipid profile of milk. The negative effects on digestibility were less with AH than of CS regardless of PF type and level.

The pursuit of reusing agribusiness residues towards decreasing their environmental impact has led to the study of its components to know their possible applications. The nejayote is the alkaline wastewater of different food products of nixtamalized corn. This study characterized the physicochemical properties of popcorn nejayote (NP) and determined its total phenolics content (TP) and antioxidant capacity by standard synthetic assays (ABTS and DPPH) and physiologically relevant ones (reducing power -RP-, hydroxyl radical scavenging activity -OH-, and iron chelation IRON). NP antioxidant capacity determined by ABTS, and DPPH methods were 387.9±0.7 and 419.3±2.9 mM Trolox equivalents (mM TE)/mL, respectively. The NP showed 296% RP compared to a control solution of coumaric acid (0.1 M). Also, the NP was obtained at 143% IRON compared to a control solution of caffeic acid (0.1 M). In the case of OH, values ranged from 27% to 45% compared with control solutions. TP was 0.26±0.006 μg gallic acid equivalents/mL (mg GAE/mL). Pearson's correlation analysis found that TP is correlated to the OH, IRON, and DPPH, while IRON activity correlates with OH and ABTS. And finally, OH correlated with DPPH. To the best of our knowledge, this study is NP's first antioxidant capacity report.

Nejayote and pericarp derived from nixtamalization are an environmental problem. Therefore, there is research interest in using these residues as new compostable and environmentally friendly materials. This work aimed to create, characterize (color, thickness, water solubility, water adsorption capacity, microstructure, and degradability), and apply biodegradable films using residues of nejayote and pericarp of nixtamalized popcorn. Three types of films were compared, pericarp (P), nejayote–pericarp (NP), and nejayote (N), and were applied to avocado stored at room temperature. Results showed that the P film was the best because it was significantly (p < 0.05) more transparent (L = 94.75 ± 2.21) and thicker (0.27 ± 0.02 mm). It had higher water adsorption capacity (162.60 ± 14.05%) and higher elastic modulus and toughness (0.004 ± 0.001 MPa, 2.25 ± 0.25 J/m³) values than the N and NP films; in addition, its microstructure showed a roughness value (Ra) of 6.59 ± 0.57 nm that was intermediate compared to other films. Moreover, the P coating slowed down the maturing process of avocado and showed a visual effect against fungal infection. All films were generally soft and had a degradation time between 11 and 12 days. The novelty of this study is to provide the alternative of using nejayote and pericarp in a film that is compostable and maintains the lifespan of avocados.

The objective was to assess in vitrorumen fermentation characteristics, methane production and biohydrogenation of unsaturated fatty acids of diets based on maize silage with two sources of protected fat (PF) from soybean (S) or linseed (L) oil, two levels of PF (0 and 6%) and two forage sources: canola silage (CS) or alfalfa hay (AH); in a factorial 2x2x2 completely randomised design. The highest (P<0.05) amount of C18:2 at the end of incubation was in the S6AH treatment (4.41mg/g DM) and of C18:3 in L6CS (1.98mg/g DM). The AH 6% PF showed the highest concentration of C18:2 cis-9 trans-11 (308 mg/g DM; P0.05). Gas production (GY) was lower with PF at 6% L vs S (150.97 vs 160.88 ml; P<0.05), and IVDMD was higher (P<0.05) with AH without PF than with 6% PF (85.04 vs 78.54%), and IVNDFD was lower with 6% L than with 6% S (62.89 vs 69.28%; P<0.05). L had the highest NH3-N concentration with CS than with AH with the same type of PF (41.27 vs 27.95 mg/dL; P<0.05). In conclusion, although methane production was not affected and in vitro digestibility and GY were reduced with linseed PF supplementation, the concentration of C18:3 and C18:1 trans-11 was increased, which could improve the lipid profile of milk. The negative effects on digestibility were improved with AH instead of CS regardless of PF type and level.

Most foods derived from plant origin are very nutritious but highly perishable products. Nowadays, the food industry is focusing on the development of efficient preservation strategies as viable alternatives to traditional packaging and chemical treatments. Hence, polysaccharide-based edible coatings have been proposed because of their properties of controlled release of food additives and the protection of sensitive compounds in coated foods. Thus, this technology has allowed for improving the quality parameters and extends the shelf life of fruits and vegetables through positive effects on enzyme activities, physicochemical characteristics (e.g., color, pH, firmness, weight, soluble solids), microbial load, and nutritional and sensory properties of coated foods. Additionally, some bioactive compounds have been incorporated into polysaccharide-based edible coatings, showing remarkable antioxidant and antimicrobial properties. Thus, polysaccharide-based edible coatings incorporated with bioactive compounds can be used not only as an efficient preservation strategy but also may play a vital role in human health when consumed with the food. The main objective of this review is to provide a comprehensive overview of materials commonly used in the preparation of polysaccharide-based edible coatings, including the main bioactive compounds that can be incorporated into edible coatings, which have shown specific bioactivities.