The objective of this study was to microencapsulate Saccharomyces boulardii using the emulsion technique. To microencapsulate the yeast, alginate sodium blended with inulin and mucilage from Opuntiaficus-indica was used as a coating material. The textural properties of the gels formed by the encapsulating materials and the in vitro viability of the yeast strain in the simulated conditions were studied. Textural profile analyses of the gels revealed differences (p < 0.05) in hardness because alginate produced stronger gels, whereas the incorporation of other hydrocolloids with alginate decreased gel strength and resulted in a more uniform, cohesive gel matrix. When alginate was blended with mucilage and inulin, encapsulated yeast presented higher counts and more viable cells, as compared to free yeast following 30 days of storage at 4 °C. Encapsulated and free yeast had 76.1% and 63.3%, respectively, of cell viability after 35 days of storage.

In this study, a partial purification and characterization of the lectins from two varieties of Phaseolus coccineus (black and purple ayocote bean) was carried out. A partial purification of the lectins was performed by affinity chromatography on fetuin-agarose. The lectins’ characterization showed that the hemagglutination activity was only inhibited by the fetuin and that the saccharides (mono-, di- and tri-saccharides) do not influence their hemagglutination capacity. A difference in the relative molecular weight between the two Phaseolus varieties was observed, 28.5 kDa for the black variety and 30.6 kDa for the purple variety. In the lectins of both Phaseolus varieties, ions were detected in their structure and influenced their hemagglutination activity, principally to the ion Ca+2; on the other hand, only the lectins of the purple variety of the Phaseolus, had a detectable ion, Cu+2. The lectins showed thermostability in the temperature range of 25 and 70 °C, on the other hand, in the pH range between 3 and 10, the lectins showed hemagglutination activity. According to the obtained results, the structural differences between the lectins obtained from both Phaseolus varieties influence their hemagglutination activity.

Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm, indicating the product of the retrogradation process. The thermal treatment reduced the crystallinity as well as short-range order. Raman spectroscopy revealed that acute changes occurred in the polysaccharide bonds after thermal treatment. This study showed that the thermal treatment affected the structural properties of ayocote bean starches, the interactions of the lipids and proteins with starch molecules and the retrogradation process of starch.

In the present study, organic volatile markers of three strawberry varieties (Albion, Festival and Frontera) during the maturation process were investigated. Forty metabolites associated with aroma in fresh strawberries were monitored during seven stages of maturation using gas chromatography–mass spectrometry (GC-MS) equipped with headspace-solid phase microextraction (HS-SPME). The data were evaluated using multivariate analysis to observe correlations between the organic volatile compound profile and the seven phenological stages of maturation for each strawberry variety. The dynamic levels of butanoic acid methyl ester, hexanoic acid methyl ester, octylcyclohexane, cyclohexane,1,1,2-trimethyl, linalool, tetradecane, and α-muurolene underwent distinctive changes in concentration during the maturation process. The multivariate analysis also allowed the identification of these compounds as possible volatile markers to measure the maturation of strawberry fruits in all three varieties. These findings highlight the importance of the timing of harvest and maturation stage in each variety to preserve or improve the desirable aromatic characteristics of strawberry fruits.

The aim of this study was to characterize Opuntia robusta parenchyma and mucilage as foodstuffs. Solute absorption of Opuntia robusta parenchyma was studied, mucilage was used to develop a mayonnaise-like product as substitute emulsifier alternative to egg yolk and oil substitute. Shelf life of mayonnaise-like product was evaluated. Scanning electron microscopy demonstrated that oxalate calcium crystal were present in the Opuntia robusta parenchyma and mucilage with druses morphology; whereas that in the mayonnaise-like product were not observed calcium oxalate crystals, due probably to the product pH is acidic. The heat treatment of parenchyma at 50 °C, 65°Brix, had highest influence on the solute absorption (about 35 %). Results revealed that best mixture was the formulated with 26.79 % oil, 62.50 % mucilage and 10.71 % whey protein. Mucilage was the component showing the highest effect on all textural characteristics of mayonnaise-like product. The storage temperature had highest effect on the textural characteristics of mayonnaise-like product than storage time. With the right combination of mucilage of Opuntia, oil and whey protein, it is possible to develop a low-fat mayonnaise with functional properties similar to those of commercial mayonnaise.

The inflorescences of Chamaedorea tepejilote Liebm. are consumed as food in Central America and southern Mexico but is an underutilized food because of its sensory characteristics, principally due to its bitter taste. However, the inflorescences of Chamaedorea tepejilote Liebm. are nutritionally promising due to their high protein content (approximately 25%). Protein isolates from pacaya were modified via three different thermal treatments to determine the effect of the treatments on the protein structures. Scanning electron microscopy indicated that the pacaya protein isolate particles had less rough and irregular surfaces with larger particle sizes due to an aggregation process when a thermal treatment was used compared to those when no thermal treatment was used. An increase in the intensity of the low molecular weight protein fractions (≤20 kDa) in the electrophoretic pattern of the proteins was observed, which was generated by the hydrolysis of the proteins by heat treatment. The modifications in the FT-IR spectra showed that thermal treatment of pacaya affected the secondary structure of its proteins, mainly when microwave treatment was used. Raman spectroscopy revealed that the α–helical structure was dominant in the proteins of pacaya and that thermal treatment increased the fraction of the β–sheet structure at the expense of the α–helical structure.

The Erythrina americana tree has been widely studied for its antioxidant and antimicrobial activity, principally of the seeds. Few studies have focused on the other tree parts. This work evaluated the effect of drying on the proximate chemical composition, IC50, and total phenolic content (TPC) of different parts of the plant from Erythrina americana. Proximate chemical composition showed significant differences between parts of the plant. Tree bark (TB) exhibited higher protein content, crude fiber, and ash. The IC50 value was significantly different in all parts of the plant; the leaves exhibited lower amounts necessary to reach this value. The drying process had a positive influence on the antioxidant activity in all parts of the plant, with mature flowers (MF) and young flowers (YF) samples. These were the samples that required the lowest concentration of all dry samples to reach the IC50 value. The TPC values showed significant differences between fresh and dry samples except for MF, according the ANOVA and Tukey test (P≤0.05). In conclusion, the drying process has potential for retaining the antioxidant activity in YD and MF.

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