Jaime David Pérez-Martínez

Antioxidant activity and content of chlorophylls and carotenoids in raw and heat-processed Jalapeño peppers at intermediate stages of ripening.

Jalapeño peppers at intermediate ripening stages (IRS) are typically discarded at the packinghouse because they are not demanded for fresh consumption or industrial processing. These peppers have been scarcely studied in terms of pigment composition and bioactivity. In this study, the profile of pigments (carotenoids and chlorophylls) and antioxidant activity were determined in raw and heat-processed Jalapeño peppers at three IRS (brown, 50% red, and 75% red). Peppers contained 64 different pigments. Chlorophylls were the most abundant pigments in raw brown peppers while capsanthin was the most abundant at the other IRS. The content of most pigments decreased due to heat treatments. Several pheophytins and cis isomers of carotenoids were generated by heat processing. Boiling and grilling consistently decreased and increased the antioxidant activity of peppers, respectively. Tested peppers showed a more complex/abundant pigment content and higher antioxidant activity than those typically reported for green and red peppers.

Effect of heat processing on the profile of pigments and antioxidant capacity of green and red jalapeño peppers.

Raw and heat-processed jalapeño peppers (green and red) were evaluated for their pigment profile and antioxidant capacity. Sixty-seven pigments were separated and characterized by HPLC-DAD-MS, including carotenoids (isomers and esters), chlorophylls, and pheophytins. The distinctive characteristics of this pepper genotype were the presence of antheraxanthin monoesters, zeaxanthin monoesters, mutatoxanthin diesters, and a higher content of free capsanthin relative to the mono- and diesterified forms. Chlorophyll a and free all-trans-lutein were the major pigments in raw green peppers, whereas free all-trans-capsanthin was the most abundant pigment in raw red peppers. Twelve compounds were generated by the heat treatments, mainly pheophytins and cis isomers of carotenoids. Heat treatments affected differentially the concentration of individual pigments. Red peppers showed a higher antioxidant capacity than green fruits. Heating caused minor changes in the antioxidant capacity of peppers.

Effect of ripening and heat processing on the physicochemical and rheological properties of pepper pectins.

Water-, chelator-, and alkali-soluble pectins were isolated from raw and heat-processed Jalapeño peppers (green and red) and their physiochemical and rheological properties were determined. The yield, tristimulus color, degree of methyl esterification, monosaccharide composition, molecular weights distribution, and protein content depended on ripening and heat processing. The viscosity properties of pectins were independent of ripening. The water-soluble pectin was the most abundant pectin. Pectins from grilled peppers showed the lowest L* values. The alkali-soluble pectin showed the highest protein content. The content of xylose, rhamnose, and mannose in pectins was highly altered by tested factors. The degree of methyl esterification of pectins ranged from 26.8 to 91.6%. The peak Mw of the main fraction of tested pectins was sequentially reduced by ripening and heat processing. Pectins from raw peppers showed the best viscosity properties.

Evaluation of the Freezing and Thawing Cryoconcentration Process on Bioactive Compounds Present in Banana Juice from Three Different Cultivars

Abstract In this research, we produced concentrates of banana juices from three different cultivars of bananas (Enano gigante and two hybrids FHIA-17 and FHIA-23) by the freezing and thawing method. To track the cryoconcentration process, different parameters were monitored in the melted fractions, such as variation of the content of soluble solids, concentration of polyphenols (Folin–Ciocalteu), reducing sugar (DNS assay), minerals (K, Mg, Ca, P, Na, Mn, Cu and B) by inductively coupled plasma-optical emission spectroscopy and the main volatile compounds by headspace-GC–MS. It was found that the solution obtained during thawing showed higher concentrations than the original solution. The concentrations of polyphenols were duplicated in FHIA-17 cultivar (758.53 mg/100 ml), and the concentrates obtained in this study proved to be good sources of K and Mg 5,054.6 mg/l and 485.4 mg/l with around 70% and 40% of the recommended daily intake (RDI), respectively. In addition, the concentrates contained a very low level of Na around 1% of the RDI. Furthermore, the cryoconcentration process of the bioactive compounds presented a sigmoid behavior, and the inflexion point in the function was proposed as stop point of the process. Finally, the main volatile compounds reported as responsible for the banana aroma were identified, and its cryoconcentration proved. These results suggest that consumption of banana juice concentrates obtained by the freezing and thawing method can provide bioactive compounds needed for health.

The effect of ripening, heat processing and frozen storage on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin from Jalapeño peppers in absence and presence of two dietary fat types

To date, there is no information in the literature regarding the bioaccessibility of capsaicinoids from natural sources. The effect of ripening and heat-processing on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin was studied in the absence and presence of two dietary fat types. The capsaicinoid bioaccessibility was also studied during the frozen storage of peppers for 6 months. Fresh green peppers showed the highest capsaicinoid bioaccessibility, as compared with that of other experimental groups. The bioaccessibility of capsaicinoids from green peppers decreased as the intensity of heat treatment increased. The dietary fat increased the bioaccessibility of capsaicin and dihydrocapsaicin in digestions with red peppers, especially that of dihydrocapsaicin. The bioaccessibility of capsaicinoids was altered by frozen storage. The Caco-2 cells incorporated capsaicin and dihydrocapsaicin (8.4% and 10.9%, respectively) but they were probably metabolized by cells.

Optimization, Modeling, and Online Monitoring of the Enzymatic Extraction of Banana Juice

This article focuses on the optimization, modeling, and online monitoring of banana juice production through an enzymatic method. In order to perform this task, a batch reactor was designed with automatic control over the temperature and the agitation speed as well as online monitoring of torque. The experiments were carried out with the Musa AAA Cavendish banana variety (Enano gigante), the main variety planted in Mexico. Three different ripening stages were evaluated. Optimization of juice extraction was evaluated as a function of the pulp/water relationship and the concentration of the enzyme complex. The results showed that the adding of water had no influence on the extraction of banana juice, and the optimal enzyme concentration per kilogram of banana pulp was found. Based on a fuzzy logic approach, it was possible to relate the initial torque with the ripeness stage. Furthermore, an observable dynamical model based on ordinary differential equations and fuzzy logic is presented. With this model, the relationship between the torque dynamic and the instant juice yield was found to depend on the amount of enzyme, the temperature, and the maturity stage of the banana used. In addition, a principal components analysis was used to classify and to relate the final juice characteristics (e.g., L, a, and b colorimetric components) to the processing conditions and the final appreciation of a group of sensorial panelists. Additionally, a robust observer was designed and implemented to filter the noise present in the torque signal and to predict the instant juice yield.

Effect of ripening, heat processing, and fat type on the micellarization of pigments from jalapeño peppers.

Raw and heat-processed (boiled and grilled) jalapeño peppers at three intermediate ripening stages (brown, 50% red, and 75% red) were digested in vitro without fat and in the presence of soybean oil (SO) or beef tallow (BT), and the micellarization of their lipid soluble pigments (LSP) was measured. The micelles from digestions with brown, 50% red, and 75% red peppers contained up to 27, 35, and 29 different LSP, respectively. Boiling and grilling decreased the micellarization of LSP from brown peppers, whereas the opposite was observed with 75% red peppers. Heat processing did not clearly affect the micellarization of LSP from 50% red fruits. The impact of fat on LSP micellarization was ripening-dependent, but the micellarization of the less polar carotenoids was always increased by SO or BT. This positive effect of fat was higher with SO than with BT.

Microencapsulation of Banana Juice from Three Different Cultivars

Abstract In order to effectively process and utilize surplus bananas and those without the quality for export, in this research it is proposed to microencapsulate the banana juice by means of spray drying and using maltodextrin as the covering material. Three cultivars Enano gigante (Musa AAA, subgroup Cavendish), and the tetraploids hybrids (AAAA), FHIA-17 and FHIA-23 were selected for this research. Being Enano gigante, the cultivar shows the highest glass transition temperature. The drying parameters were established, depending upon the ratio of juice/maltodextrin and the drying air temperature. The optimal drying air temperature was 220°C for the three cultivars with a 20% juice/maltodextrin ratio for both the Enano Gigante and the FHIA-23, while in the FHIA-17 there were no significant differences between the juice/maltodextrin ratios. The morphology and size distribution of the microcapsules were observed by a scanning electron microscopy. The number of particles is directly proportional to the temperature and inversely proportional to the juice/maltodextrin ratio. A Weibull particle size distribution was common to all treatments. There is a correlation between the principal components and clustering analyses with the optimization of the system. The principal components analysis considers three Weibull parameters (obtained from the particle size distribution) and the powders moisture percentage.