Physical quality and in vitro starch digestibility of bread as affected by addition of extracted malva nut gum

Malva nut gum (MNG) was extracted by alkaline solution. The previous studies showed that the extract had viscosity and gelling properties as well as inhibited α-amylase activity in starch solution 1.5–2.0 folds higher than that of original malva nut gum. This research was aimed to investigate the α-amylase inhibitory effect of alkaline-extracted MNG in solid food and to determine physical properties of MNG-containing bread. The scanning electron microscopy of in vitro digestibility with α-amylase of MNG-containing breads showed less porosity and more undigested starch granules remained intact with the matrix compared to control. This finding was consistent with the reduction of glucose (33–40%) and maltose (23–39%) levels compared to that of control after α-amylase digestion for 180 min in a dialysis system. The results showed that extracted MNG significantly (p < 0.05) increased loaf volume, and moisture content by 1.5–12%, and 8.2–12.8%, respectively compared to that of control. Addition of extracted MNG in bread formulation significantly reduced moisture loss and firmness of the bread crumb after storage for three days.     

Influence of xanthan gum and gluten on in vitro digestibility and textural properties of rice bread

Starch digestibility of gluten-free bread has been expected to be suppressed for the purpose of decreasing glycemic response. The objective of this study was to investigate the effects of adding xanthan gum and gluten on starch and protein digestibility of rice bread prepared using the developed recipe involving pickering stabilization of foams and emulsions. The extent of starch digestion of gluten-free bread was suppressed by adding 2% xanthan gum from 79.8% to 57.3%. This suppressive effect was diminished by using gluten and that of rice bread containing 2% xanthan gum and 20% gluten was 75.5%. The extent of starch digestion of gluten-free bread was similar or less than that of bread containing gluten. The gluten-free bread with 2% xanthan gum had significantly lower loaf volume, porosity, and sticker structure of breadcrumb than the control. The suppressive effects of xanthan gum on starch and protein digestion were mainly dependent on reducing accessibility of the enzyme into the inner structure.     

Comparison of in vitro starch digestibility methods for predicting the glycaemic index of grain foods

BACKGROUND: In vitro starch digestibility tests are useful for the prediction of glycaemic index (GI). However, there are no internationally recognised methods and no one method has been found to be suitable for all food types. This study compared six in vitro methods, using four grain foods, including those with a varied particle size and soluble fibre content. Method variations included using chewing or mincing, mincing with or without amylase and incubation in a restricted versus non‐restricted system. Hydrolysis index (HI) values, calculated from the starch digestibility curves and GI prediction equations were used to compare the in vitro results to GI. RESULTS: HI values for five of the six methods ranked all foods in the same order as the GI values. Using a GI prediction equation (predicted GI_HI) the mincing (without amylase) non‐restricted method had the smallest standard error of prediction between the predicted GI_HI and GI values. This method was then validated using 14 grain foods and demonstrated a significant correlation (r = 0.93, P < 0.01) between the in vitro starch digestibility and reported GI responses. CONCLUSIONS: The non‐restricted mincing method showed good potential as a new in vitro starch digestibility method for predicting GI in grain foods. Copyright © 2007 Society of Chemical Industry     

Pasting behaviour, textural properties and freeze-thaw stability of wheat flour-crude malva nut (Scaphium scaphigerum) gum system

The effect of replacement of crude malva nut gum (CMG) at 0%, 2.5%, 5%, 7.5% and 10% w/w on pasting behaviour, textural properties and freeze-thaw stability of wheat flour was investigated. Replacement of wheat flour by CMG significantly elevated (p < 0.05) the peak viscosity (128-669 RVU), hot paste viscosity (77-363 RVU), breakdown (51-306 RVU) and final viscosity (157-557 RVU) of wheat flour pastes. Pasting temperature (59-85 °C) of the flour decreased with increasing CMG content. The textural parameters including hardness, springiness, cohesiveness, gumminess and chewiness of the mix gels decreased with higher level of CMG. Freeze-thaw stability measurement revealed that wheat gel mixtures containing higher level (7.5% and 10%) of CMG decreased syneresis more than 80% after 3 freeze-thaw cycles, when compared to non-CMG sample. The rate of syneresis depended on CMG concentration and number of freeze-thaw cycles. The results demonstrated that higher viscosity, softer texture and lower syneresis of wheat gel could be attained using CMG.     

Textural and sensory quality of poultry meat batter containing malva nut gum, salt and phosphate

The effect of crude malva nut gum (CMG) addition to poultry breast meat batters formulated with different salt levels (0-3 g/100 g NaCl) and phosphate (0 and 0.5 g/100 g) was studied. Increasing the salt level resulted in an overall increase of cook yield, and the addition of CMG (0.2 g/100 g) further improved yield at all salt levels. The cooked batter with 2 g/100 g NaCl and phosphate showed the highest values for all of textural parameters. However, the cohesiveness and chewiness were reduced by the addition of 0.2 g/100 g CMG. In addition, the effect of incorporating CMG (0.0, 0.2 and 0.6 g/100 g) into commercial type frankfurters, made from mechanically deboned chicken meat (MDCM), was evaluated. Frankfurters with 0.2 g/100 g CMG showed low cooking loss and had better textural properties than the frankfurters without CMG. Frankfurters lightness and redness were reduced due to CMG. Sensory analysis results indicated that the frankfurters with 0.2 g/100 g CMG were more firm and elastic. Overall, the study indicates the potential use of CMG to improve yield and textural parameters of meat products.     

Microstructures of starch granule,starch digestibilities and predicted glycaemic index of common bean mutants in Taiwan

In this study, the microstructure of starch granule and in vitro starch digestibility were compared in de‐coated seeds of common bean variety Hwachia and its NaN₃‐induced mutants. Significant differences in starch granule size (between 17.92 and 27.00 μm), total starch content (between 436.5 and 456.8 mg per seed) and resistant starch content (between 51.6 and 203.3 mg per seed) were found among mutants. Both boiling and autoclaving decreased resistant starch content in processed common beans. Significant difference in predicted gylcaemic index (pGI) (between 48.82 and 64.55%) for processed beans also existed among mutants. However, 96 h of 4 °C storage increased resistant starch content in processed common beans, possibly resulted from starch retrogradation during storage. Mutants SA‐05, SA‐08 and SA‐31, which have smaller seed weight and lower pGI (average of 50.08%) compared to Hwachia (pGI of 57.05%), can be used to produce common bean based low GI dietary carbohydrate.     

Influence of tetraploid wheat (Triticum dicoccum) on low glycaemic index pizza base processing and its starch digestibility

The present study aimed to utilise Dicoccum wheat (DW), barley (BF) and soya flour (SF) in the development of low in vitro starch digestibility (IVSD) and estimated glycaemic index (EGI) PB. The BF and SF are mixed (1:1) (BFSF) and used to replace DW at 25%, 50% and 75% level and compared with 100% DW. The quality characteristics (rheological, physical, textural and chemical), IVSD and EGI of PB were determined. The incorporation of BFSF to DW increased the farinograph water absorption capacity (58.1%–64.2%) and mixing tolerance index (21-68 FU), and decreased the dough development time (4.3–2.8 min) and amylograph pasting properties, respectively. Further, the thickness, shear force and redness were decreased and lightness and yellowness increased. Based on the physico-sensory studies, 50% of BFSF along with emulsifier’s incorporation was optimum without affecting any sensory parameters and this PB had decreased IVSD (31) and EGI (54) when compared to the control 37 and 63, respectively.     

瓜尔胶对木薯淀粉消化性、糊化特性、水分运动性的影响

研究瓜尔胶对木薯淀粉消化性的影响,采用Englyst法测定淀粉的消化性,比较与分析了瓜尔胶/木薯淀粉体系的糊化特性、水分运动性、微观结构的差异,从而探究瓜尔胶对木薯淀粉消化性的影响机理。结果表明:瓜尔胶添加量较低时,糊化后冷却至37℃的体系结构疏松、具有较高的水分运动性,瓜尔胶促进淀粉的酶解,抗消化淀粉含量较低;继续提高瓜尔胶添加量时,糊化后冷却至37℃的体系结构越加紧密、水分运动性降低,瓜尔胶形成空间位阻,降低酶与底物的可及性,瓜尔胶反而抑制淀粉的酶解,抗消化淀粉含量较高。      

Physical,sensory, in-vitro starch digestibility and glycaemic index of granola bars prepared using sucrose alternatives

Granola bars were prepared using barley flakes, groundnut bits, cocoa powder, sucrose and/or sucrose alternatives (coconut sugar, fructooligosaccharide and inulin). Apart from sensory acceptance, nutritional composition, energy values and glycaemic responses (glycaemic index, GI and glycaemic load, GL) of the bars were evaluated. Physico-chemical properties and sensorial acceptance of granola bar made with coconut sugar and fructooligosaccharide were on par with those made with sucrose. Further, all formulated granola bars, except with inulin, were intermediate moisture foods. GI of all five formulations of granola bars was <55; ranging between 51 and 54.9, corresponding to low glycaemic food. Granola bars with coconut sugar had high GL (≥20), while bars prepared with FOS, inulin and without sugar were in the medium range (>10 to <20). Effect of choice of raw materials, complexity of matrix structure and particle size of ingredients on GI and GL of the bars is explained.     

In vitro starch digestibility of fresh and sun‐dried faba beans (Vicia faba L.)

Fresh and sun‐dried faba beans (Vicia faba L.) were cooked, stored for various times at 4 °C and analysed for available starch (AS), resistant starch (RS) and fibre‐associated resistant starch (FARS) contents as well as α‐amylolysis. Fresh beans required a shorter cooking time (25 min) than dried beans (158 min). Cooked fresh faba beans had a higher AS content than cooked dried faba beans. The AS content in both decreased during cold storage, with fresh beans showing a smaller decrease than dried beans with increasing storage time. Cooked fresh faba beans also had a higher total RS content than cooked dried faba beans, although a greater increase in RS content was recorded in the latter upon storage. Starch retrogradation was more prominent in cooked dried faba beans than in cooked fresh faba beans, as indicated by the consistently higher FARS content. The α‐amylolysis rate decreased with increasing storage time, i.e. long‐stored (72 h) cooked faba beans exhibited slower starch digestion, and differences were recorded between fresh and dried beans. The predicted glycaemic index ranged between 60.9 and 58.0% for cooked fresh faba beans and between 57.9 and 55.8% for cooked dried faba beans, which is suggestive of slow glucose release from starch in faba beans. Copyright © 2007 Society of Chemical Industry     

Reducing the glycaemic index and increasing the slowly digestible starch content in gluten‐free cereal‐based foods: a review

Commercially available gluten‐free (GF) cereal‐based foods are generally characterised by a lower nutritional quality than their gluten‐containing counterparts, relatively lower resistant starch (RS) content, along with higher glycaemic index (GI) often being reported. To overcome this nutritional imbalance, extensive research has been conducted to investigate the preparation of a new generation of staple GF products. This review reported the main strategies currently adopted in GF cereal‐based food recipes to formulate products with overall slowly digestible starch properties. They are mainly obtained by the utilisation of alternative ingredients to be incorporated into standard food formulation (including native starch and GF flours) or by technological treatments that may contribute to impact starch digestibility. Considering data from in vitro digestion trials, indications suggested that, aiming to obtain a RS content of about 5% (dry weight) and lowering the in vitro GI values, the minimum high amylose starch (amylose >60%) replacement level in GF bread and cookie formulations should be in the order of 20% by weight of total flours. Overall, with respect to un‐substituted GF foods, two‐ to three‐times higher RS contents, along with a parallel in vitro GI decrease (up to ?50%), were obtained for GF pasta and ready‐to‐eat snacks enriched with legume flours at inclusion levels from 40% to 100% by weight of total flours. The use of flours from pseudocereals (e.g., quinoa, amaranth and buckwheat) with and without sourdough did not always guarantee favourably slowly digestible starch GF foods.     

Physicochemical properties,digestibility and expected glycaemic index of high amylose rice differing in length-width ratio in Sri Lanka

Gelatinization, pasting, digestibility and estimated glycaemic index of six high amylose rice varieties differing in length/width ratio were studied. Amylose content ranged narrowly (27.8–29.1%). Resistant starch content ranged from 0.44% to 1.4%. In contrast to gelatinisation enthalpy, gelatinisation temperature (GT) ranged narrowly (76.7–77.4 °C). For all rice varieties, melting temperature of amylose-lipid complex I and II was around 99 °C and 110 °C, respectively. The enthalpy of amylose-lipid complex I and II ranged between 0.18–0.87 and 0.23–0.55, respectively. Expected in vitro glycaemic index (GI) of all tested varieties was similar (88.2–92.4). The results showed that the size of the rice grain (length/width) and resistant starch content had no apparent impact on the GI of high amylose rice. The dominant factors determining the digestibility and glycaemic response of the tested high amylose rice varieties seemed to be amylose content and the GT. Besides the pasting temperature, other pasting properties varied significantly but were not correlated to starch digestibility and estimated GI among the six rice varieties. Thus, RVA pasting properties, except for pasting temperature, may not be good predictors for the GI of these high amylose rice.     

Proximal composition and in vitro starch digestibility in flaxseed‐added corn tortilla

BACKGROUND: The effect of addition of flaxseed flour (10:90, 15:85 and 20:80, w/w) on the chemical composition and starch digestibility of corn tortilla was investigated. Tortillas were baked and frozen in liquid nitrogen, freeze‐dried, ground and analyzed for fat, protein, ash, total starch (TS), available starch (AS) and resistant starch (RS) contents as well as for starch hydrolysis rate and predicted glycemic index (pGI). Tortillas made from commercial nixtamalized corn flour were used as control sample. RESULTS: Flaxseed flour addition increased the fat and protein content of tortilla, whereas TS and AS decreased. TS was 15.25% lower in the 20% flaxseed‐containing tortilla as compared to the control sample. The AS content was 12.65% lower in the composite tortilla. RS content in the samples ranged between 1.92% for the control sample and 5.08% for the tortilla containing 20% flaxseed. The reduced enzymatic starch hydrolysis rate and pGI recorded for the flaxseed‐added tortilla, indicated slow digestion features. CONCLUSIONS: Flaxseed‐added tortilla might be used to increase the consumption of α‐linolenic acid in the daily diet and modulate starch digestibility of corn tortilla. This kind of product may be used by people with special diet reqirements. Copyright © 2008 Society of Chemical Industry     

Study on the physicochemical properties and in vitro digestibility of starch from yam with different drying methods

Four methods were applied to dry yam slices, and then, starches were isolated from dried yam slices. Starch isolated from fresh yam was as the study control, and physicochemical properties and in vitro digestibility of starches were studied. The results showed that the amylose content ranged from 12.62% to 28.25%, water‐binding capacity (WBC) from 111.67% to 262.88%, paste clarity from 2.1% to 6.23%, resistant starch (RS) from 66.60% to 88.49% and crystallinity from 11.27% to 25.52%. Compared with the control starch, hot air‐drying at 60 °C significantly decreased amylose content, paste clarity, RS and crystallinity, while increasing the WBC. Low levels of rapidly digestible starch and glucose and high RS levels were found in the starch from freeze‐drying yam. Digestibility of the starches was significantly correlated with amylose content, WBC, paste clarity and swelling power. The starch samples were divided into three groups by principal component analysis (PCA).     

Rheological/textural properties of starch and crude hsian‐tsao leaf gum mixed systems

The Effects of hsian‐tsao leaf gum (HG) on the rheological/textural properties of non‐waxy starches were studied. Pronounced interactions between starch and HG were observed. The rheological properties, including pseudo‐gel viscosity in the rapid visco‐analyser test, storage and loss moduli in the dynamic rheological test, as well as firmness in the texture analyser test, of the mixed gels generally improved with increasing gum concentration to a certain level, then deteriorated with further increase in gum concentration. The critical gum concentration for the development of optimal rheological properties depended on the starch type and concentration. Within the concentration range studied, mixed systems with wheat starch could generally reach the highest pseudo‐gel viscosity, firmness, and storage modulus if the starch/HG ratio was appropriate, followed by those with corn and tapioca starch. Copyright © 2003 Society of Chemical Industry