Betalains and their applications in food: The current state of processing, stability and future opportunities in the industry.

Betalains are water-soluble nitrogenous pigments with coloring properties and antioxidant activities, which is why they have been incorporated into several foods. However, their use is limited by their instability in response to different factors, such as, pH, oxygen, water activity, light, metals, among others. In this work, a review of up-to-date and relevant information is presented on the primary natural sources of betalains. Additionally, the advantages and disadvantages of the primary betalain extraction techniques are discussed and compared. The results of these studies were focused on the stability of betalains when incorporated into foods, either in pure or encapsulated form, and they are discussed through different technologies. Lastly, the most relevant information related to their stability and a projection of their promising future applications within the food industry is presented.

Thermal properties and volatile compounds profile of commercial dark-chocolates from different genotypes of cocoa beans (Theobroma cacao L.) from Latin America.

There is a growing interest in the identification of chemometric markers that allow the distinction and authentication of dark-chocolates according to their cocoa geographical origin and/or genotype. However, samples derived from Latin American cocoa, including specimens from North and South America, have not been studied in this context. An exploration of the melting behavior, fat composition, bioactive content, and volatile profile of commercial darkchocolates was conducted to identify possible patterns related to the genotype and/or origin of cocoa from Latin America. The melting properties were evaluated by DSC and related to fat content and fatty acids profile. Total polyphenol, anthocyanin, methylxanthine, and catechin content were analyzed. Finally, the volatile compounds were extracted and identified by HS-SPME/GC-MS and were analyzed through Principal Component Analysis (PCA) and the Hierarchical Cluster Analysis Heatmap (HCA Heatmap). The fatty acids profile showed a relationship with the melting properties of dark chocolate. The samples exhibited two glass-transition temperatures (Tg) at ≈19 °C and ≈25.5 °C, possibly related to traces of unstable polymorphic forms of monounsaturated triacylglycerides. The analysis of bioactive compounds demonstrated great variability among samples independent of the cocoa origin, genotype, and content. The PCA and HCA Heatmaps allowed discriminating against the chocolates in relation to the cocoa origin and genotype. Compounds like tetramethylpyrazine, trimethylpyrazine, benzaldehyde, and furfural could be considered as dark-chocolate aroma markers derived from Latin American cocoas (North American region). The 2-phenylethyl alcohol, 2-methylpropanoic acid, 2,3-butanediol, 2-nonanone, and limonene for derived from South America. And the 2-phenylethyl acetate, 3-methyl-butanal, and cinnamaldehyde could allow to distinguishing between regional genotypes.

In silico analysis of antidiabetic potential of phenolic compounds from blue corn (Zea mays L.) and black bean (Phaseolus vulgaris L.).

The growing interest in bioactive compounds, especially in polyphenols, is due to their abundance in the human diet and potentially positive effects on health. The consumption of polyphenols has been shown to possess anti-diabetic properties by preventing insulin resistance or insulin secretion through different signaling pathways, this effect is associated with their capacity to exert genomic modulations. Several studies have suggested that polyphenols could also bind to cellular proteins and modulate their activity, however, the mechanisms of action underlying their beneficial effects are complex and are not fully understood. The aim of this work was to characterize phenolic compounds present in blue corn and black bean extracts as well as identify their potential interactions with target proteins involved in diabetes pathogenesis using in silico approach. Total polyphenols content of both blue corn and black beans was identified using UPLC-ESI/qTOF/MS and quantified by colorimetric assays. In this work we identified twenty-eight phenolic compounds in the extracts, mainly anthocyanins, flavonols, hydroxycinamic acids, dihydroxybenzoic acids, flavones, isoflavones, and flavanols. Interactome of these compounds with thirteen target proteins involved in type 2 diabetes mellitus was performed in-silico. In total, 312 bioactive compounds/protein interaction analyses were acquired. Molecular docking results highlighted that nine of the top ten interactions correspond to anthocyanins, cyanidin 3-glucoside with 11ß-HS, GFAT, PPARG; delphinidin 3-glucoside with 11ß-HS, GFAT, PTP and RTKs; and petunidin 3-glucoside with 11ß-HS and PTP. These proteins are involved in mechanisms regulating functions such as inflammation, insulin resistance, oxidative stress, glucose and lipid metabolism. In conclusion, this work provides a prediction of the potential molecular mechanism of black bean and blue corn polyphenols, specifically anthocyanins and could constitute new pathways by which compounds exert their antidiabetic benefits.

Identification of predominant yeasts associated with artisan Mexican cocoa fermentations using culture-dependent and culture-independent approaches.

The process of cocoa fermentation is a very important step for the generation or aromatic compounds, which are attributable to the metabolism of the microorganisms involved. There are some reports about this process and the identification of microorganisms; however, there are no reports identifying the yeasts involved in a Mexican cocoa fermentation process using molecular biology techniques, including restricted fragment length polymorphism (RFLP) and denaturing gradient gel electrophoresis (DGGE). The aim of this study was to identify the main yeast species associated with Mexican cocoa fermentations employing culture-dependent and -independent techniques achieving two samplings with a 1 year time difference at the same site. Isolation of the microorganisms was performed in situ. Molecular identification of yeast isolates was achieved by RFLP analysis and rDNA sequencing. Total DNA from the microorganisms on the cocoa beans was utilized for the DGGE analysis. Bands from the DGGE gels were excised and sequenced. Nineteen isolated yeasts were identified (al specie level), three of which had never before been associated with cocoa fermentations worldwide. The detected predominant yeast varied from one technique to another. Hanseniaspora sp. resulted dominant in DGGE however Saccharomyces cerevisiae was the principal isolated species. In conclusion, the culture-dependent and -independent techniques complement each other showing differences in the main yeasts involved in spontaneous cocoa fermentation, probably due to the physiological states of the viable but non culturable yeasts. Furthermore important differences between the species detected in the two samplings were detected.

Effect of fermentation time and drying temperature on volatile compounds in cocoa.

The effects of fermentation time and drying temperature on the profile of volatile compounds were evaluated after 2, 4, 6, and 8 fermentation days followed by drying at 60, 70 and 80°C. These treatments were compared with dry cocoa controls produced in a Samoa drier and by a sun-drying process. A total of 58 volatile compounds were identified by SPME-HS/GC-MS and classified as: esters (20), alcohols (12), acids (11), aldehydes and ketones (8), pyrazines (4) and other compounds (3). Six days of fermentation were enough to produce volatile compounds with flavour notes desirable in cocoa beans, as well as to avoid the production of compounds with off-flavour notes. Drying at 70 and 80°C after six fermentation days presented a volatile profile similar to the one obtained by sun drying. However, drying at 70°C represents a lower cost. Given the above results, in the present study the optimal conditions for fermentation and drying of cocoa beans were 6days of fermentation, followed by drying at 70°C.

Acaricidal effect of essential oils from Lippia graveolens (Lamiales: Verbenaceae), Rosmarinus officinalis (Lamiales: Lamiaceae), and Allium sativum (Liliales: Liliaceae) against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

Acaricidal effects of three essential oils extracted from Mexican oregano leaves (Lippia graveolens Kunth), rosemary leaves (Rosmarinus officinalis L.), and garlic bulbs (Allium sativum L.) on 10-d-old Rhipicephalus (Boophilus) microplus (Canestrini) tick larvae were evaluated by using the larval packet test bioassay. Serial dilutions of the three essential oils were tested from a starting concentration of 20 to 1.25%. Results showed that both Mexican oregano and garlic essential oils had very similar activity, producing high mortality (90-100%) in all tested concentrations on 10-d-old R. microplus tick larvae. Rosemary essential oil produced >85% larval mortality at the higher concentrations (10 and 20%), but the effect decreased noticeably to 40% at an oil concentration of 5%, and mortality was absent at 2.5 and 1.25% of the essential oil concentration. Chemical composition of the essential oils was elucidated by gas chromatography-mass spectrometry analyses. Mexican oregano essential oil included thymol (24.59%), carvacrol (24.54%), p-cymene (13.6%), and y-terpinene (7.43%) as its main compounds, whereas rosemary essential oil was rich in a-pinene (31.07%), verbenone (15.26%), and 1,8-cineol (14.2%), and garlic essential oil was rich in diallyl trisulfide (33.57%), diallyl disulfide (30.93%), and methyl allyl trisulfide (11.28%). These results suggest that Mexican oregano and garlic essential oils merit further investigation as components of alternative approaches for R. microplus tick control.

Antimicrobial and antioxidant activities of Mexican oregano essential oils (Lippia graveolens H. B. K.) with different composition when microencapsulated in beta-cyclodextrin.

AIMS: To study how the antimicrobial and antioxidant activities of Lippia graveolens essential oils with different composition are affected after the microencapsulation process with beta-cyclodextrin (beta CD). METHODS AND RESULTS: Three Mexican oregano essential oils (EOs) with different carvacrol/thymol/p-cymene ratios (38 : 3 : 32, 23 : 2 : 42, 7 : 19 : 35) were used in this study. Microencapsulation was carried out by spray-drying. Antimicrobial activities were measured as MBC (minimal bactericidal concentration) using 0.05%/0.10%/0.20% (w/v) dilutions of EOs against Escherichia coli ATCC 11229, Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538. Antioxidant activities were determined by the 2,2'-diphenyl-1-picrylhydrazil (DPPH) method. EOs showed antimicrobial and antioxidant activity, but microencapsulation preserved the antimicrobial activity in all cases and increased the antioxidant activity from four- to eightfold. CONCLUSIONS: Although the Lippia essential oils were from the same species, their composition affects the biological activities before and after the microencapsulation process, as well as encapsulation efficiency. Our study supports the fact that microencapsulation of EOs in beta-cyclodextrin preserves the antimicrobial activity, improves the antioxidant activity and acts as a protection for EOs main compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: Microencapsulation affects positively EOs main compounds, improves antioxidant activity and retains antimicrobial activity, enhancing the quality of the oils.

Generation of aroma compounds from Ditaxis heterantha by Saccharomyces cerevisiae.

Ditaxis heterantha, a plant of the Euphorbiaceae family, is growing wild in the semiarid regions of Mexico. The seed endosperm contains yellow pigments (carotenoids). By high-pressure liquid chromatography the total pigment (TP) was separated into seven fractions: two of them, heterathin (F4) and ditaxin (F5), characterized as apocarotenoids, represent 80% of TP. Both molecules have double bonds, which seem to be the target for degradation and aroma formation. In this work, TP, F4, and F5 were supplied to nine cultures able to degrade lutein. From these strains, only one (identified as Saccharomyces cerevisiae) was able to produce aromas from either TP or F4. Using TP as substrate, the produced aromas were 4-oxo-isophorone (1), isophorone (2), cinnamic aldehyde (6), 3-hydroxy-beta-cyclocitral (7), safranal (8), geranyl (9), 3-oxo-alpha-ionone (10), 3-oxo-alpha-ionol (11), 3-oxo-7,8-dihydro-alpha-ionone (12), and eugenol (13). Of these aromas, only seven were produced from F4: (1), (2), (7), (8), (10), (11), and (12). In both cases, safranal was the main degradation product (30%). The enzymatic activity responsible for this effect was found in the cytosolic fraction and detected only when S. cerevisiae was grown in the presence of TP or F4.