M. S. Sajeev

Physical and functional properties of arrowroot starch extrudates.

Arrowroot starch, a commercially underexploited tuber starch but having potential digestive and medicinal properties, has been subjected to extrusion cooking using a single screw food extruder. Different levels of feed moisture (12%, 14%, and 16%) and extrusion temperatures (140, 150, 160, 170, 180, and 190 degrees C) were used for extrusion. The physical properties--bulk density, true density, porosity, and expansion ratio; functional properties such as water absorption index, water solubility index, oil absorption index, pasting, rheological, and textural properties; and in vitro enzyme digestibility of the extrudates were determined. The expansion ratio of the extrudates ranged from 3.22 to 6.09. The water absorption index (6.52 to 8.85 g gel/g dry sample), water solubility index (15.92% to 41.31%), and oil absorption index (0.50 to 1.70 g/g) were higher for the extrudates in comparison to native starch (1.81 g gel/g dry sample, 1.16% and 0.60 g/g, respectively). The rheological properties, storage modulus, and loss modulus of the gelatinized powdered extrudates were significantly lower (P < 0.05) and these behaved like solutions rather than a paste or a gel. Hardness and toughness were more for the samples extruded at higher feed moisture and lower extrusion temperature, whereas snap force and energy were higher at lower feed moisture and temperature. There was a significant decrease in the percentage digestibility of arrowroot starch (30.07% after 30 min of incubation with the enzyme) after extrusion (25.27% to 30.56%). Extrusion cooking of arrowroot starch resulted in products with very good expansion, color, and lower digestibility, which can be exploited for its potential use as a snack food.

Ultrastructural and Starch Digestibility Characteristics of Sweet Potato Spaghetti: Effects of Edible Gums and Fibers

Considering the importance of pasta as a food having low starch digestibility, and the global increase in diabetes, an attempt was made to develop low glycaemic spaghetti from sweet potato incorporating gums and fibers. Gums such as guar, xanthan, and locust bean were incorporated at 0.5, 1.0, and 1.5 g/100 g mix while the fibers such as apple, oat, and wheat were incorporated at 10 and 20 g/100 g mix levels along with 1.0 and 1.5 g/100 g of xanthan gum, respectively. Gum fortified spaghetti retained more protein on cooking than fiber + xanthan gum fortification. Higher swelling index was observed for gum fortified spaghetti than fiber + xanthan gum fortification, whereas cooking loss followed a reverse pattern. Lowest in vitro starch digestibility was observed for xanthan gum (1.5%) fortification, which was significantly less than the fiber + xanthan gum fortification. Resistant starch was retained to a high extent in the fortified spaghetti. The estimated glycaemic index for control spaghetti was 66.62, which could be reduced to 58–60 and 57–59 through 1.5% gum 20% fiber + xanthan gum fortification, respectively. Gums increased the firmness (N) and decreased the toughness (Ns) of dry spaghetti, while cooking drastically reduced the firmness. Formation of starch-gum-protein network was evident in the scanning electron microscopic pictures of most of the gum fortified samples. Ultrastructural studies showed that fiber + xanthan gum fortification had less firm structure of cooked spaghetti than xanthan gum alone. The study showed that guar gum and xanthan gum (1.5%) fortification can produce sweet potato spaghetti with medium glycaemic index of 58.

Cooking behavior and starch digestibility of NUTRIOSE® (resistant starch) enriched noodles from sweet potato flour and starch

The effect of a resistant starch source, NUTRIOSE® FB06 at 10%, 15% and 20% in sweet potato flour (SPF) and 5% and 10% in sweet potato starch (SPS) in reducing the starch digestibility and glycaemic index of noodles was investigated. While NUTRIOSE (10%) significantly reduced the cooking loss in SPF noodles, this was enhanced in SPS noodles and guar gum (GG) supplementation reduced CL of both noodles. In vitro starch digestibility (IVSD) was significantly reduced in test noodles compared to 73.6g glucose/100g starch in control SPF and 65.9 g in SPS noodles. Resistant starch (RS) was 54.96% for NUTRIOSE (15%)+GG (1%) fortified SPF noodles and 53.3% for NUTRIOSE (5%)+GG (0.5%) fortified SPS noodles, as against 33.8% and 40.68%, respectively in SPF and SPS controls. Lowest glycaemic index (54.58) and the highest sensory scores (4.23) were obtained for noodles with 15% NUTRIOSE+1% GG.

Sustained release enteric coated tablets of pantoprazole: Formulation, in vitro and in vivo evaluation

In this study, an attempt was made to deliver pantoprazole in a sustained manner using delayed release tablets. The tablets were prepared by the wet granulation method using HPMC, cassava starch and polyvinyl pyrrolidine as polymers, Avicel PH 102 (MCC) as filler and potato starch as binder. The prepared tablets were evaluated for hardness, mass variation, friability and drug content uniformity, and the results were found to comply with official standards. The prepared tablets were coated using an enteric coating polymer such as cellulose acetate phthalate, Eudragit L100 and drug coat L100 by the dip coating method. The in vitro release was studied using pH 1.2 acidic buffer and pH 6.8 phosphate buffer and the study revealed that the prepared tablets were able to sustain drug release into the intestine. The anti-ulcer activity was evaluated by a water immersion stress induced ulcer model. The enteric coated pantoprazole tablets significantly reduced ulcer formation.

Textural and Gelatinization Characteristics of White, Cream, and Orange Fleshed Sweet Potato Tubers (Ipomoea Batatas L.)

Sweet potato is an important food crop having nutritive value in terms of starch, carotein, and minerals. The acceptability and overall quality of the products depend on their textural and rheological attributes. Cooking quality of the tubers could be related to the textural, pasting, and gelatinization properties, which vary depending on the flesh color of the tubers. Also, being a promising ingredient in many of the traditional and industrial products, the physico-chemical and functional properties of sweet potato flour are very much important for their selection for developing various value added products. The textural, gelatinization, and pasting characteristics of white, cream, and orange fleshed sweet potato tubers were analyzed and their thermal softening behavior was modeled by linear regression and fractional conversion techniques. Significant variations were observed in the properties among different varieties (p < 0.05). Kinetics of texture degradation on cooking were explained by first-order and dual-mechanism first-order models and the latter was found to be more suitable. The first three principal components explained about 85% of the total variation in texture profile parameters, gelatinization, and pasting properties. Though there was no similarity in the textural properties of the raw tubers among the varieties of same flesh color group, the quality of the cooked tubers and flours of different varieties in the same group are similar as revealed by the multivariate analysis.

Functionality of Tuber Starches

Abstract Root and tuber crops form an important part of the diet in many tropical belts and are rich in starch; cassava and sweet potato being widely used for starch extraction. Unlike cereal starches, these starches show a wide range of property and are hence used in food and industry. Modified starches from these crops are becoming more important. Until recently, only cassava and sweet potato starches were studied in detail, but of late, the other tuber starches have been subjected to lot of investigations. In this chapter, extraction, properties, uses, and modifications have been described in detail. Among the physicochemical properties, granule size and shape and structural properties studied by XRD and molecular analysis, amylose content, and structure are very diverse among the starches. Wide variation in swelling characteristics and solubility patterns and thermal properties determined by differential scanning calorimetry indicates not only the effect of origin but also the environmental and processing conditions. Viscosity, pasting, and rheological features also exhibit a similar trend. Digestibility, another important attribute in food applications, has been investigated in detail. Various modifications—physical, chemical, and enzymatic—have been carried out on these starches to suit to different applications and discussed.