Edith Agama-Acevedo

Some structural, physicochemical and functional studies of banana starches isolated from two varieties growing in Guerrero, México.

Two varieties of green fruit banana growing in Guerrero State Mexico, were used for starch isolation. Starch yields from the bananas varieties “macho” and “criollo” were 43.8% and 11.8%, respectively. Thermal transition temperatures assessed by differential scanning calorimetry (DSC) were higher for “criollo” than for “macho” starch but the enthalpy changes in both starches were not different. Both starches showed A-type diffraction pattern, until now not reported for banana starches. Light microscopy revealed some structural characteristics of banana starches as shape and size and eccentric birefringence was observed under polarized light. The iodine-stained differed in their blue color intensity. The viscosity profiles of both samples evaluated with the Rapid Visco Analyzer (RVA) were similar, and the gelatinization temperatures agree with those obtained by DSC. The pastes formed from banana starches in general were opaque and the storage temperature had a slight effect on clarity.

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 digestibility and resistant starch content of some industrialized commercial beans (Phaseolus vulgaris L.)

Commercial bean products were studied in terms of chemical composition and starch digestibility. In general, commercial cooked flours did not show differences in protein and ash contents. Canned beans also did not show statistical differences (α=0.05) in protein, but they were different in ash, perhaps due to botanical variety. Lipid content varied in the different flours, due to the formulation used in their preparation, whereas the canned bean samples had similar lipid values. Canned samples had the highest available starch (AS) values. These results suggest that the drying of samples decreases AS. Canned beans had the lowest total resistant starch (RS) values, and the flours obtained from canned seeds had the highest. These results agree with AS content in the samples. Retrograded resistant starch (RS type 3) showed the same pattern as RS (type 2+type 3), but with lower absolute values. The in vitro α-amylolysis rate for canned beans and commercial flours was lower than for samples dried in the laboratory. Thus, the additional drying step increased the hydrolysis rate of the samples. Therefore, depending on the specific dietetic use of beans, appropriate processing methods and formulations are needed.

Pasta with unripe banana flour: physical, texture, and preference study.

Banana is a starchy food that contains a high proportion of undigestible compounds such as resistant starch and nonstarch polysaccharides. Products with low glycemic response such as pasta are considered favorable to health. The objective of this study was to use unripe banana flour to make spaghetti with low-carbohydrates digestibility and evaluate its physical and texture characteristics, as well as consumer preference. Formulations with 100% durum wheat semolina (control) and formulations with 3 semolina: banana flour ratios (85: 15, 70: 30, and 55: 45) were prepared for spaghetti processing. The use of banana flour decreased the lightness and diameter of cooked spaghetti, and increased the water absorption of the product. Hardness and elasticity of spaghetti were not affected by banana flour, but adhesiveness and chewiness increased as the banana flour level in the blend rose. Spaghettis prepared in the laboratory (control and those with banana flour) did not show differences in preference by consumers. In general, the preference of spaghettis with different banana flour level was similar. The addition of a source of undigestible carbohydrates (banana flour) to spaghetti is possible without affecting the consumer preference.

Isolation and partial characterization of amaranth and banana starches

Alternative sources from different botanical origin were used for starch isolation. Chemical analysis and functional properties were studied in amaranth seed and banana fruit starches. Chemical composition in both starches was different; banana starch presented higher protein, fat and ash levels than that from amaranth. Botanical origin of these starches contributes notably in their chemical composition. Blue value and λmax gave information on starch components: amaranth starch is classified as waxy type and banana starch as normal. Functional properties were evaluated; amaranth starch was more soluble than banana starch, but at higher temperatures amaranth showed lower swelling values than banana starch. The results of freeze-thaw stability suggest that amaranth starch can be used in frozen products. Apparent viscosity studies showed that amaranth starch paste has higher viscosity than banana starch, but the former starch presented higher stability during the 30-min test.

Physicochemical, digestibility and structural characteristics of starch isolated from banana cultivars

Banana starches from diverse varieties (Macho, Morado, Valery and Enano Gigante) were studied in their physicochemical, structural and digestibility features. X-ray diffraction indicated that the banana starches present a B-type crystallinity pattern, with slight difference in the crystallinity level. Macho and Enano Gigante starches showed the highest pasting temperatures (79 and 78°C, respectively), whilst Valery and Morado varieties presented a slight breakdown and higher setback than the formers. Morado starch presented the highest solubility value and Valery starch the lowest one. The swelling pattern of the banana starches was in agreement with their pasting profile. All banana starches showed a shear-thinning profile. The resistant starch (RS) fraction was the main fraction in the uncooked banana starches. Morado variety showed the highest amount of slowly digestible starch (SDS) and the lowest RS content reported until now in banana starches. Banana starch cooked samples presented an important amount of SDS and RS. Molecular weight and gyration radius of the four banana starches ranged between 2.88-3.14×10(8)g/mol and 286-302nm, respectively. The chain-length distributions of banana amylopectin showed that B1 chains (DP 13-24) is the main fraction, and an important amount of long chains (DP≥37) are present. The information generated from this study can be useful to determine banana varieties for starch isolation with specific functionality.

In vitro starch digestibility of tortillas elaborated by different masa preparation procedures

ABSTRACT Starch digestibility was evaluated in freshly prepared tortillas elaborated from masa obtained from different procedures (laboratory-made masa, commercial masa, and nixtamalized corn flour) and from laboratory-made masa with added commercial hydrocolloid, and stored for 24, 48, and 74 hr. Tortillas prepared with commercial masa had the highest available starch (AS) content and the commercial tortillas had the lowest, showing a decrease in AS content when storage time increased. Tortilla of commercial masa showed the lowest resistant starch (RS) content that agrees with the AS measured. However, tortilla of laboratory-made masa presented the highest AS and RS contents. RS increased with storage time, a pattern that is related to the starch retrogradation phenomenon observed when retrograded resistant starch (RRS) was quantified. Commercial tortillas showed predicted glycemic index (pGI) values of 62–75% using a chewing/dialysis procedure (semi in vitro method). Index values were lower than those d...

PASTA ADDED WITH CHICKPEA FLOUR: CHEMICAL COMPOSITION, IN VITRO STARCH DIGESTIBILITY AND PREDICTED GLYCEMIC INDEX PASTA ADICIONADA CON HARINA DE GARBANZO: COMPOSICIÓN QUÍMICA, DIGESTIBILIDAD IN VITRO DEL ALMIDÓNY PREDICCIÓN DEL ÍNDICE GLUCÉMICO

Abstract Pasta was prepared with of durum wheat flour mixed with chickpea flour at two different levels and its chemical composition, in vitro starch digestibility and predicted glycemic index were assessed. Protein, ash, lipid, and dietary fiber content increased while total starch decreased with the chickpea flour level in the composite pasta, all in accordance to the composition of the legume flour. Potentially available starch decreased and resistant starch (RS) increased by adding chickpea flour to the pasta. The main indigestible starch component in composite spaghetti was the fiber-associated RS, representing up to 50 % of total RS levels. The starch hydrolysis index (HI) decreased as chickpea flour in the pasta increased, reflecting the slow and low digestion of the starch in the leguminous ingredient. Predicted glycemic index was lower in spaghetti added with chickpea flour than in durum wheat-control pasta. Pasta added with chickpea flour might be a dietetic alternative for people with low-calorie requirements. Resumen Se elaboró pasta mezclando sémola de trigo con harina de garbanzo a dos niveles y se evaluó su composición química, digestibilidad del almidón in vitro y se predijo el índice glucémico. El contenido de proteína, ceniza, lípidos y fibra dietética incrementó mientras que el almidón total disminuyó con el contenido de harina de garbanzo en la pasta, esto debido a la composición de la harina de la leguminosa. El contenido de almidón disponible disminuyó y el almidón resistente (AR) incrementó con la adición de la harina de garbanzo a la pasta. El principal componente del almidón no digestible en el espagueti con harina de garbanzo fue el AR asociado a fibra, que representó más del 50 % del AR total. El índice de hidrólisis (IH) del almidón disminuyó con el incrementó del nivel de harina de garbanzo en la pasta, reflejando la baja y lenta digestión del almidón de la leguminosa. La predicción del índice glucémico fue menor en el espagueti adicionado con harina de garbanzo que la muestra control. La pasta adicionada con harina de garbanzo puede ser una alternativa dietética para personas con bajos requerimientos calóricos. Palabras clave: Índice glucémico, composición química, pasta, garbanzo, almidón resistente, fibra dietética

Potential of plantain peels flour (Musa paradisiaca L.) as a source of dietary fiber and antioxidant compound

Peel from unripe plantain is obtained when the pulp is used for the next production process as starch isolation or dry flour. Plantain peel flour (PPF) was obtained and its chemical composition, composition of the dietary fiber (DF), polyphenol content, antioxidant capacity, and functional properties were studied. PPF had more relevant amounts of protein, ash, total starch, and total dietary fiber (TDF). The main component of DF was the insoluble fraction, with a higher level of cellulose than hemicellulose and lignin. In the insoluble fraction uronic acid was the most predominant acidic monosaccharide, while mannose was in the soluble fraction. Extractable polyphenols were found in the lowest amount, but showed the highest antioxidant capacity. Water- and oil-holding capacity values increased when the temperature of the test increased. The PPF with high DF content, high antioxidant capacity, and functional characteristics could be used as a functional ingredient for the elaboration of food products.

Composite Durum Wheat Flour/Plantain Starch White Salted Noodles: Proximal Composition, Starch Digestibility, and Indigestible Fraction Content

ABSTRACT In search of a way to improve the nutritional profile of noodles, we prepared them with various mixtures of durum wheat flour and isolated plantain starch, and tested their proximal composition. Cooked noodles were assessed for in vitro starch digestibility, indigestible fraction content, and predicted glycemic index. The protein content declined with the addition of plantain starch. Both total starch (TS) level and the content of starch available for digestible enzymes (AS) decreased as the plantain starch level increased, a pattern that may be related to increased starch lixiviation during cooking of noodles containing plantain starch. There was an inverse pattern for resistant starch (RS). RS content in control (durum wheat flour) noodles was ≈50% lower than in the samples containing plantain starch. The soluble indigestible fraction (SIF) content in all samples was higher than the insoluble counterpart (IIF). The total indigestible fraction varied according to the wheat substitution level. Al...