Effect of ultrasound and steam treatments on bioaccessibility of ß-carotene and physicochemical parameters in orange-fleshed sweet potato juice.

Several health benefits have been associated to orange-fleshed sweet potato owing to the existence of various bioactive compounds, including ß-carotene. The purpose of this study was to establish the effect of ultrasound and steam treatment on the bioaccessibility of ß-carotene, total polyphenols, antioxidant activity, polyphenol oxidase, peroxidase activity, and color in the orange-fleshed sweet potato juice. Sweet potato juice was processed using ultrasound (0.66 W cm-2 and 8 min), steam (2 min), and a combination of steam and ultrasound. The bioaccessibility of ß-carotene was increased in processed sweet potato juice, with samples treated by ultrasound showing the highest bioaccessibility (76.6%). Processing had no effect on antioxidant or enzyme activity, but resulted in significant changes in the color of the juice. As a processing technology, ultrasound enables preservation or improvement of the quality of sweet potato juice, and when conbined with other treatments, facilitates the development of new products.

Canola oil/candelilla wax oleogel improves texture, retards staling and reduces in vitro starch digestibility of maize tortillas.

BACKGROUND: Maize tortilla staling is a major drawback that affects its commercialization and consumption, and so novel methods for retarding staling are continuously being explored. The present study evaluated the effect of adding a canola oil/candelilla wax oleogel (CWO; 0. 2, 4 and 6 g 100 g-1 ) to a basic masa formulation (water, 60 g 100 g-1 ; nixtamalized maize flour, 40 g 100 g-1 ) on the texture, staling and in vitro starch digestibility of maize tortillas made using a hot plate (200 °C). RESULTS: Textural analysis showed that CWO reduced hardness and increased the tensile strength of tortillas. Fourier transform infrared analysis indicated that the retrogradation of starch chains, quantified in terms of the intensity ratio 1047/1022, was reduced by oleogel incorporation. In vitro starch digestibility tests showed that tortillas containing CWO had lower readily digestible and slowly digestible starch fractions compared to the control tortilla without oleogel. CONCLUSION: The formation of amylose-lipid inclusion complexes and the formation of an oily physical barrier around starch granules were postulated as mechanisms underlying the reduced starch digestibility. © 2019 Society of Chemical Industry.

A novel, simple, economic and effective method for retarding maize tortilla staling.

BACKGROUND: Staling of maize tortillas is a major drawback affecting their manufacture, commercialization and consumption. The development of methods that may help retard staling of maize tortillas is an ongoing research topic. In this work, a novel, simple, economic and effective method is proposed, based on adding completely gelatinized nixtamalized maize flour (GMF) dispersion to the basic masa formulation recipe (water, 600 g kg-1 ; nixtamalized maize flour, 400 g kg-1 ) in substitution of 50, 100 and 150 g kg-1 of water. RESULTS: Masa added with GMF showed increased water retention capacity, reduced freezable water content and improved flow and dynamic rheological properties and produced tortillas with decreased firmness. The infrared 1047/1022 cm-1 spectral ratio indicated that a more disordered starch granule arrangement was formed, while enthalpy peaks associated with starch retrogradation decreased. All the above indicators were more pronounced the higher was the GMF content. CONCLUSION: This work showed that GMF can play the role of a self-hydrocolloid anti-staling agent by retarding the retrogradation of maize starch and deterring the loss of water and rheological properties of masa and the increase in undesirable sensory characteristics of tortilla such as increased firmness. © 2018 Society of Chemical Industry.

Colonic Fermentation of Unavailable Carbohydrates from Unripe Banana and its Influence over Glycemic Control.

The aim of this study was to evaluate the effect of the colonic fermentation of unavailable carbohydrates from unripe banana (mass - UBM - and starch - UBS) over parameters related to glucose and insulin response in rats. Wistar male rats were fed either a control diet, a UBM diet (5 % resistant starch - RS) or a UBS diet (10 % RS) for 28 days. In vivo (oral glucose tolerance test) and in vitro (cecum fecal fermentation, pancreatic islet insulin secretion) analyses were performed. The consumption of UBM and UBS diets by Wistar rats for 28 days improved insulin/glucose ratio. Also, pancreatic islets isolated from the test groups presented significant lower insulin secretion compared to the control group, when the same in vitro glucose stimulation was done. Total short chain fatty acids produced were higher in both experimental groups in relation to the control group. These findings suggest that UBM and UBS diets promote colonic fermentation and can influence glycemic control, improving insulin sensitivity in rats.

Flaxseed (Linum usitatissimum L.) and its total non-digestible fraction influence the expression of genes involved in azoxymethane-induced colon cancer in rats.

The influence of flaxseed (Linum usitatissimum L.) and its total non-digestible fraction (TNDF) on the expression of genes involved in azoxymethane (AOM)-induced colon cancer in Sprague Dawley rats was analyzed. The dose used in the animal model was two tablespoons of flaxseed per day, which is the dose recommended for humans. Flaxseed significantly decreased the crypt multiplicity (10.50 ± 3.5) compared with the AOM treatment (34.00 ± 11.0), which suggests that flaxseed exhibits a preventive effect against colon cancer. Both treatments (flaxseed and TNDF) influence the overexpression of genes involved in cell cycle arrest and mitochondrial apoptosis: p53, p21, bcl-2, bax and caspase-3. Flaxseed induced the expression of p53 and p21, whereas TNDF triggered the p21-independent expression of p53. This finding suggests that both of these treatments induced cell cycle arrest. In addition, TNDF induced mitochondrial apoptosis because the TNDF + AOM group exhibited the expression of caspase-3, decreased bcl-2 expression and increased bax expression. These results suggest that the expression of the analyzed genes is associated with the presence of dietary antioxidants linked to the cell wall of flaxseed.

Proteomic analysis of the enzymes involved in the starch biosynthesis of maize with different endosperm type and characterization of the starch.

BACKGROUND: The characterization of starch maize with different endosperm type and the proteomic analysis of its biosynthetic enzymes at 20 and 50 days after pollination (DAP) was carried out. RESULTS: There were differences between both endosperm types at 20 DAP, mainly in starch accumulation, amylose content, granule size and crystallinity percentage, whereas at 50 DAP the differences found were not relevant in the case of starch content, granule size, chain length distribution and thermal properties. SSSI, SBEIIb and GBSSI enzymes were identified; however, SBEIIb was only identified in two samples: floury endosperm at 20 DAP and vitreous at 50 DAP. CONCLUSION: Starch did not show differences in its morphological or structural characteristics in either endosperm on reaching maturity. Starch biosynthetic enzymes identified by matrix-assisted laser desorption/ionization-time of flight did not show a relationship to starch structure.

Digital image analysis of diverse Mexican rice cultivars.

BACKGROUND: Digital image analysis has an important role in geographical provenance of grains, as it can provide parameters of size, shape and color, which are important quality parameters for the design of engineering processes such as drying and milling of grains. In this study, digital image analysis was used to classify nine rice cultivars based on different morphometric parameters using the three sides of the grain (lateral, ventral and axial), Feret diameter, and 10 different form factors and color parameters (CIE L*, a* and b*). RESULTS: Result of principal component analyisis was an equation with seven variables (area, perimeter, length, width, thickness, sphericity and color), which was useful for distinguishing between nine different cultivars. The morphometric and color parameters for the Mor A-98 and Mor A-92 varieties showed they had 88% similarity. The variability was expressed with a confidence of 95%. CONCLUSION: Multivariate analysis indicated that the lateral side is the most sensitive for the classification of Mexican rice grains because of its color and morphometric characteristics. These results showed the application of image analysis for the future classifications of grains.

Physicochemical and digestibility properties of double-modified banana ( Musa paradisiaca L.) starches.

Banana starch was chemically modified using single (esterification or cross-linking) and dual modification (esterification-cross-linking and cross-linking-esterification), with the objective to increase the slowly digestible starch (SDS) and resistant starch (RS) concentrations. Physicochemical properties and in vitro digestibility were analyzed. The degree of substitution of the esterified samples ranged from 0.006 to 0.020. The X-ray diffraction pattern of the modified samples did not show change; however, an increase in crystallinity level was determined (from 23.79 to 32.76%). The ungelatinized samples had low rapidly digestible starch (RDS) (4.23-9.19%), whereas the modified starches showed an increase in SDS (from 10.79 to 16.79%) and had high RS content (74.07-85.07%). In the cooked samples, the esterified starch increased the SDS content (21.32%), followed by cross-linked starch (15.13%). Dual modified starch (cross-linked-esterified) had the lowest SDS content, but the highest RS amount. The esterified and cross-linked-esterified samples had higher peak viscosity than cross-linked and esterified-cross-linked. This characteristic is due to the fact that in dual modification, the groups introduced in the first modification are replaced by the functional group of the second modification. Temperature and enthalpy of gelatinization decreased in modified starches (from 75.37 to 74.02 °C and from 10.42 to 8.68 J/g, respectively), compared with their unmodified starch (76.15 °C and 11.05 J/g). Cross-linked-esterified starch showed the lowest enthalpy of gelatinization (8.68 J/g). Retrogradation temperature decreased in modified starches compared with unmodified (59.04-57.47 °C), but no significant differences were found among the modified samples.

In vitro colonic fermentation and glycemic response of different kinds of unripe banana flour.

This work aimed to study the in vitro colonic fermentation profile of unavailable carbohydrates of two different kinds of unripe banana flour and to evaluate their postprandial glycemic responses. The unripe banana mass (UBM), obtained from the cooked pulp of unripe bananas (Musa acuminata, Nanicão variety), and the unripe banana starch (UBS), obtained from isolated starch of unripe banana, plantain type (Musa paradisiaca) in natura, were studied. The fermentability of the flours was evaluated by different parameters, using rat inoculum, as well as the glycemic response produced after the ingestion by healthy volunteers. The flours presented high concentration of unavailable carbohydrates, which varied in the content of resistant starch, dietary fiber and indigestible fraction (IF). The in vitro colonic fermentation of the flours was high, 98% for the UBS and 75% for the UBM when expressed by the total amount of SCFA such as acetate, butyrate and propionate in relation to lactulose. The increase in the area under the glycemic curve after ingestion of the flours was 90% lower for the UBS and 40% lower for the UBM than the increase produced after bread intake. These characteristics highlight the potential of UBM and UBS as functional ingredients. However, in vivo studies are necessary in order to evaluate the possible benefit effects of the fermentation on intestinal health.

Effect of the addition of common bean (Phaseolus vulgaris L.) flour on the in vitro digestibility of starch and undigestible carbohydrates in spaghetti.

Spaghetti is considered to be a slowly digestible starch food, a feature ruled by the particular physical properties of the product. Several studies have been reported to increase nutritional value of spaghetti, using legumes. We have studied the addition of common bean flour on the starch in vitro digestibility. Spaghetti was prepared with semolina and different concentrations of common bean flour (0%, 15%, 30%, and 45%, w/w). Proximate analysis, optimal cooking time, and cooking loss were estimated in crude spaghetti. Total, available, and resistant starches, indigestible fractions, and in vitro starch hydrolysis kinetics were accomplished in cooked spaghetti. Pasta with 30% and 45% of common bean flour showed higher values of protein. Particularly, the lowest cooking time was observed for composite spaghetti with 45% of common bean flour. There was a significant increase in cooking loss when common bean flour in the composite was added. Composite spaghetti samples with increasing common bean flour showed decreasing values of total starch but an important increase in the resistant starch (RS) level and indigestible insoluble fraction values. Plain pasta made with semolina showed the highest enzymatic hydrolysis rate, which decreased when common bean flour was added to the spaghetti. Spaghetti with a higher level of common bean flour was more slowly available, which may have positive implications for human health.

Obtención de jarabe fructosado a partir de almidón de plátano (Musa paradisíaca L) caracterización parcial / Obtention of fructose syrup from plabtain (Musa paradisíaca L) starch partial characterization

El consumo de fructosa se ha incrementado en los últimos años, llegando a reemplazar a la sacarosa en diversas aplicaciones industriales. Usualmente, la fructosa se obtiene por isomerización continua de la glucosa obtenida a partir del almidón de maíz. Sin embargo, debido al aumento del precio de este grano, es necesario identificar nuevas fuentes de almidones que puedan ser utilizadas en la producción de fructuosa. En este trabajo se reportan algunas propiedades fisicoquímicas del jarabe de fructuosa (JFP) obtenido a partir del almidón de plátano Musa paradisíaca L. El JFP se obtuvo mediante dos reacciones secuenciales, catalizadas por enzimas que transformaron el almidón a glucosa y, finalmente, la glucosa a jarabe de fructuosa mediante isomerización. En la isomerización se logró una conversión media de 41,3 por ciento, obteniéndose un promedio de 63,3 mg·ml¯¹ de fructosa a las 80h de proceso. El color del JFP, medido en unidades de densidad óptica (UDO), fue alto (1,78) en comparación con la escala recomendada para jarabe de fructosa (0,025-0,200), lo que probablemente se debió a que el JFP tiene un mayor contenido de cenizas (2,07 por ciento) que los jarabes comerciales. La viscosidad del producto fue baja en comparación con los jarabes comerciales. Los resultados demuestran que es posible obtener jarabe fructosado a partir del almidón de plátano, con características comparables a los jarabes comerciales, mediante un procedimiento enzimático.

Digestibilidad del almidón en diferentes variedades de frijol (phaseolus vulgaris L) / Starch digestibility in different bean (phaseolus vulgaris L) varieties

Se estudió la composición química y la digestibilidad del almidón de cuatro variedades de frijol común (Phaseolus vulgaris L.). No se encontraron diferencias estadísticas (p£0,05) en el contenido de proteína y el contenido de lípidos fue bajo pero sin diferencias apreciables. Estos frijoles son buena fuente de minerales (3,67-5,15 por ciento cenizas). El valor de almidón total (AT) menor fue para la variedad Flor de Mayo (34,70 por ciento) y el mayor para Peruano (42,81 por ciento) y Mayocoba (40,24 por ciento). Los valores mayores de almidón disponible (AD) se determinaron en las variedades Flor de Mayo (32,27 por ciento) y Peruano (31,60 por ciento), y los menores en las variedades Mayocoba (22,87 por ciento) y Negro (21,7 por ciento). La variedad Flor de Mayo presentó el menor valor (2,43 por ciento) de almidón resistente (AR), y las variedades con el mayor valor de AT (40,24-42,81 por ciento) también tuvieron el valor más alto de AR (5,41-6,4 por ciento). Las variedades Flor de Mayo y Peruano mostraron los mayores porcentajes (p£0,05) de hidrólisis (34-37 por ciento), lo que coincidió con sus valores de AD. La predicción del índice glucémico (pIG) fue mayor en la variedad Peruano (68,69), y menor en Mayocoba (57,88) y Negro (58,40). Estos valores de pIG se consideran bajos

Effect of storage time on in vitro digestion rate and resistant starch content of tortillas elaborated from commercial corn masas.

Tortilla samples were elaborated by four small commercial factories in Mexico, employing masas prepared with the traditional nixtamalization process. Samples were stored at 4 degrees C for up to 72 hours and their chemical composition and in vitro starch digestibility features were evaluated. Chemical composition did not change with the storage time, but soluble carbohydrates decreased slightly during storage. A significant decrease in available starch content upon storage was observed, concomitant with increased resistant starch (RS) levels. These changes are possibly due to retrogradation. Retrograded resistant starch (RRS) values increased with storage time; in some samples, RRS represented more than 75% of total RS whereas in others it only accounted for 25%. The digestion rate (DR) in the freshly prepared tortillas was similar for the various samples, but after 72 h storage some differences among tortillas were found. Also, when a single tortilla sample was compared throughout the different storage times, lower DRs were determined in samples subjected to prolonged storage, which is related to the concomitant. increase in RRS. The differences found among the various tortilla samples may be due to minor variations in the commercial processing conditions and to the use of different corn varieties.

Effect of storage time on in vitro digestion rate and resistant starch content of tortillas elaborated from commercial corn masas

Se elaboraron tortillas utilizando masa a partir de cuatro tortillerías, la cual fue obtenida mediante el proceso tradicional de nixtamalización. Las muestras fueron almacenadas a 4 ºC hasta por 72 h y se determinó su composición química y digestibilidad del almidón in vitro. La composición química no cambio con el tiempo de almacenamiento, pero los carbohidratos solubles disminuyeron ligeramente durante el almacenamiento. Se observó que el contenido de almidón disponible disminuyó y el almidón resistente (AR) se incrementó con el tiempo de almacenamiento. Estos resultados se deben posiblemente a la retrogradación del almidón. Los contenidos de almidón resistente retrogradado (ARR) se incrementaron con el tiempo de almacenamiento; en algunas muestras el ARR representó más del 75 por ciento del AR total y en otras muestras fue sólo el 25 por ciento. La velocidad de digestión (VD) en las tortillas recién elaboradas fue similar, pero se encontraron diferencias significativas entre las tortillas almacenadas por 72 h. Al comparar las VDs de las tortillas a los diferentes tiempos, se encontró que disminuyeron significativamente con el tiempo de almacenamiento, lo cual esta relacionado con el incremento en el contenido de ARR. Las diferencias determinadas en las tortillas pudo deberse a variaciones en las condiciones del proceso de nixtamalización que usa cada tortillería así como la variedad de maíz utilizada

In vitro starch digestibility changes during storage of maize flour tortillas.

Nixtamalized maize flours elaborated by four factories in Mexico were used for tortilla preparation. Samples were stored at 4 degrees C for up to 72 h and their in vitro starch digestibility features were evaluated. Moisture content was different between flour and tortilla but no evident relation could be established. Protein and lipid levels were lower in tortillas than in flour but ash content was not different in both samples. A decrease in available starch content was observed upon 48 h cold storage (4 degrees C), changes that were concomitant with increased total resistant starch (RS) levels. These changes were due mainly to retrogradation, as suggested by the increased retrograded resistant starch (RRS) levels recorded in stored tortillas; in some samples, RRS represented up to 100% of total RS. The digestion (alpha-amylolysis) rate (DR) of freshly prepared tortillas differed for the various samples. Although the amylolysis patterns for fresh and 72 h-stored tortillas were similar, lower DR values were shown for the stored materials. The differences found among the various tortilla samples may be due to variations in processing conditions during commercial maize flour preparation, and to the use of different maize varieties.

Thermal and viscoselastic properties of starch isolated from Mexican corn hybrids

El objetivo de este trabajo fue caracterizar las propiedades térmicas (temperatura de gelatinización y temperatura de fusión del almidón retrogradado) y reológicas (viscoelasticidad y viscosidad en unidades Bravender) del almidón aislado de diferentes maíces híbridos cultivados en México. La temperatura de gelatinización de los almidones fluctuó de 71,5 a 74,7 °C. La temperatura de fusión del almidón retrogradado fue menor a los 7 y 14 días de almacenamiento que la temperatura de gelatinización, mientras que la entalpía de fusión fue, en general, mayor sólo a los 14 días de almacenamiento. El perfil reológico para las pastas formadas durante las primeras dos etapas (calentamiento cocimiento) de una cinética de tres etapas de calentamiento/enfriamiento, correspondió al de geles viscoelásticos débiles, con el módulo elástico mayor que el módulo viscoso (G'>G''), mientras que en la tercera etapa (enfriamiento), las pastas se comportaron como geles mayormente elásticos (G'>> G''). El viscoamilograma de las pastas de almidón mostró viscosidades máximas alrededor de los 93 °C para mezclas al 5 por ciento (p/v) de sólidos y 87 °C para mezclas con 10 (p/v) por ciento de sólidos. El análisis estadístico mostró diferencias significativas entre los almidones con respecto a su composición química, así como en sus propiedades térmicas y reológicas. Los resultados sugieren que estos almidones podrían utilizarse en alimentos no procesados, por su alta tendencia a retrogradar y su comportamiento de geles viscoelásticos "débiles" durante el procesamiento.

Laboratory scale production of maltodextrins and glucose syrup from banana starch.

Banana starch was isolated to obtain maltodextrin by enzymatic hydrolysis with a heat-stable alpha-amylase. The maltodextrin obtained had a dextrose equivalent (DE) between 7-11 and showed suitable chemical characteristics for food application. Additionally, banana maltodextrin had a greater white color value and total color difference (delta E) than a sample of commercial maltodextrin. Further saccharification of the maltodextrins was carried out with amyloglucosidase and pullulanase at 60 degrees C during 24 h obtaining a glucose syrup. Chemical characteristics of banana glucose syrup were compared with those of a commercial syrup obtaining similar results. Nevertheless, the color of banana glucose syrup was clearer than the one of a sample of commercial syrup. However, it showed lower color stability than the commercial sample, i.e., the color of banana glucose syrup changed as a function of storage time. Banana starch may be used to obtain maltodextrins and glucose syrups with similar chemical characteristics of those obtained from maize starch. Particularly, the color of banana maltodextrin is adequate for its use in food products.

Laboratory scale production of maltodextrins and glucose syrup from banana starch

ABSTRACT: Banana starch was isolated to obtain maltodextrin by enzymatic hydrolysis with a heat-stable _-amylase. The maltodextrin obtained had a dextrose equivalent (DE) between 7-11 and showed suitable chemical characteristics for food application. Additionally, banana maltodextrin had a greater white color value and total color difference (_E) than a sample of commercial maltodextrin. Further saccharification of the maltodextrins was carried out with amyloglucosidase and pullulanase at 60 ÆC during 24 h obtaining a glucose syrup. Chemical characteristics of banana glucose syrup were compared with those of a commercial syrup obtaining similar results. Nevertheless, the color of banana glucose syrup was clearer than the one of a sample of commercial syrup. However, it showed lower color stability than the commercial sample, i.e., the color of banana glucose syrup changed as a function of storage time. Banana starch may be used to obtain maltodextrins and glucose syrups with similar chemical characteristics of those obtained from maize starch. Particularly, the color of banana maltodextrin is adequate for its use in food products.

Salmonella en carnes crudas: un estudio en localidades del estado de Guerrero / Salmonella in raw meats: a study in towns of Guerrero

Las gastroenteritis y enfermedades diarreicas ocupan el segundo lugar de morbilidad en el estado de guerrero. Estos padecimientos en muchos casos son causados por la presencia de salmonella en los alimentos. Para conocer las condicicones higénicas de algunos de ellos, se analzaron un total de 336 muestras de carnes crudas, recolectadas en nueve localidades de la entidad para determinar la presencia de salmonela, utilizando los métodos estánddar. Un total de 109 muestras estuvieron contaminadas con este patógeno, lo cual representa un 32.44 por ciento de postividad. Las muestras que presentaron los mayores índices de salmonella fueron chorizo y longaniza, carne de cerdo y cecina, comprobándose una calidad microbiológica un tanto deficiente en estos productos

Gastroenteric and diarrhoes diseases are the second cause of morbidity in the state of Guerrero, Mexico. Many cases are the result of salmonella in food. 336 meat samples, collected from nine towns in Guerrero state, were analyzed to check the presence of Salmonella. 109 samples (32.44%) were contaminated with this bacterium The kinds of meat with salmonella mainly were: sausage, pork meat and cured meat. The microbiology quality was little deficient in this products.