In Vitro Starch Digestibility Research Articles

Influence of Dehulled African Breadfruit Substitution on Starch Digestibility, Dietary Fibre and Glycemic Index of High-Fibre Snack Bars from Maize and Coconut Flour Blends

In this article, African breadfruit seeds were dehulled and made into flour alongside maize and coconut, and the flours were analyzed for their particle sizes and nutritive value. Snack bars were prepared by substituting different levels of dehulled African breadfruit (Treculia africana) seed flour with maize flour at a constant level of coconut grits viz., 0:95:5=T0, 20:75:5=T1, 25:70:5=T2, 30:65:5=T3, 35:60:5=T4, 95:0:5=T5. The snack bars were analyzed for their starch fractions, in vitro starch digestibility, glycemic index and dietary fibre fractions. Rapidly digestible starches (RDS) ranged from 26.32 – 34.62 %, slowly digestible starches (SDS) ranged from 34.46 – 38.71 %, and resistant starch (RS) content was from 3.15 to 9.24 %, while total starch content (TS) was 62.44 – 72.42 %. In vitro starch digestibility (IVSD) and glycemic index (IVGI) ranged from 34.29 – 57.48 % and 47.32 – 57.34 % respectively. Dietary fibre content showed 3.46 – 5.18%, 6.66 – 13.72% and 10.72 – 17.18 % for soluble dietary fibre (SDF), insoluble dietary fibre (IDF) and total dietary fibre (TDF) respectively. SDS and SDF increased, while IVSD and IVGI decreased significantly (p<0.05) with increase in dehulled African breadfruit flour substitution. The higher the TDF, the lower the glycemic index (GI) of the snack bars. All snack bars prepared showed high fibre content and low – medium GI, indicating that they could be useful for consumers interested in weight management or battling diabetes.

Characterization of Ozonated Pearl Millet and Sorghum Starches: Pasting Profile, Functional Properties, In Vitro‐Digestibility, Molecular Interactions, and Morphology

AbstractThe present research is undertaken to study the effect of ozonation on isolated pearl millet starch (PMS) and sorghum starch (SS), at various concentrations (0.06, 0.08, and 0.1 L min−1) for 60 minutes. The ozonated starches is evaluated for the techno‐functional properties, in vitro starch digestibility, pasting properties, morphological characteristics, X‐ray diffraction, and FTIR interactions. Functional properties such as water and oil absorption capacity and solubility, paste clarity (PC), gel consistency (GC), and freeze‐thawing stability (FTS) increased significantly (p ≤ 0.05). However, swelling power (SP) increased for all treatments with rise in temperature but a reverse trend is observed with an increase in ozone treatment. Although, reduction in vitro starch digestibility (IVSD) for treated PMS i.e. 44.59 to 29.20 g 100 g−1 maltose and 30.80–28.76 g 100 g−1 maltose for SS is observed. Slight difference is observed for the color values is observed. Higher values of peak and final viscosity whereas, lower breakdown viscosity, and setback viscosity are observed for all treatments. The crystalline pattern of PMS and SS remained unaffected with ozone treatment, whereas relative crystallinity (RC) decreased with ozone treatment. SEM images confirmed indentations, and enlargement of surface pores for ozonated starches. While, FTIR spectroscopy revealed a slight decrease in the peak intensity.

Effect of Euryale ferox seed shell extract addition on the in vitro starch digestibility and predicted glycemic index of wheat-based bread

The inhibitory effects of Euryale ferox seed shell extract (EFSSE) on the activity of α-amylase and α-glucosidase were studied. EFSSE (0.25 % to 2 %) was used to fortify bread and analyzed the in vitro starch digestibility (IVSD) digestion kinetics, and the predicted glycemic index (pGI) was estimated. The swarm intelligence supervised neural network (SISNN) technique was applied for the predictive simulation of digestion kinetics and pGI. Principal component analysis (PCA) with proportional odds modeling (POM) was used to find the most sensitive component based on the sensory attributes of bread. The inhibitory effect of EFSSE on α-amylase and α-glucosidase in terms of IC50 was 62.95 and 52.06 μg/mL, respectively. Fortification of bread with EFSSE could affect loaf volume, hardness, and color. Euryale ferox seed shell extract could decreased the rate of hydrolysis of bread. EFSSE (2 %) had a strong inhibitory impact, as evidenced by the drop in glycemic index from 94.61 to 61.66. SISNN-based kinetics was much better as compared to mathematical modeling-based digestion kinetics. Findings of the present study have shown that EFSSE could be employed as an additive to produce lower glycemic index functional bread.

The influence of high pressure processing and germination on anti-nutrients contents, in vitro amino acid release and mineral digestibility of soybeans

To study the effects of germination and high-pressure processing (HPP) on the digestibility of nutrients and anti-nutrient contents. soybeans were treated by germination and HPP for 5 and 10 min at 300, 450 and 600 MPa. The bioaccessibility of minerals (Fe, Zn, Ca), free amino acids (FAA) and starch was determined. The inhibitory activities of phytic acid, tannin and trypsin inhibition activity were studied. The results showed that HPP significantly improved FAA release. The in vitro starch digestibility (IVSD) increased by 2.42 times after germination. Germination and 450 MPa/10 min treatments significantly increased Fe digestibility by 2.07 and 2.06 times, respectively (P < 0.05). Germination and HPP significantly increased Zn digestibility by 2.50 and 1.51 times (P < 0.05), respectively, and HPP increased digestibility of Ca 1.91 times on average. The phytic acid content decreased by 52.4 % and 6.1 % after germination and 300 MPa treatments (P < 0.05), respectively. For tannin, 450 MPa/10 min decreased its content (P < 0.05). The trypsin inhibitor content was reduced by 22.3 % and 10.76 % by germination and 450 MPa/5 min (P < 0.05), respectively. Therefore, the obtained results contribute to enhancing mineral digestibility, releasing FAA, reducing anti-nutrition factors and expanding the utilization of soybeans as food ingredients in the food industry.

Effects of a Bacillus-based direct-fed microbial on in vitro nutrient digestibility of forage and high-starch concentrate substrates.

Two experiments evaluated the effects of a Bacillus-based direct-fed microbial (DFM) on in vitro dry matter (DM) and neutral detergent fiber (NDF; experiment 1) and starch (experiment 2) digestibility of a variety of ruminant feedstuffs. In experiment 1, 10 forage sources were evaluated: ryegrass, alfalfa hay, leucaena, corn silage, spinifex, buffel grass, flinders grass, Mitchell grass, Rhodes grass hay, and Queensland bluegrass. Experimental treatments were control (forages with no probiotic inoculation; CON) and forage sources inoculated with a mixture containing Bacillus licheniformis and Bacillus subtilis (3.2 × 109 CFU per g; DFM). In vitro DM and NDF digestibility were evaluated at 24- and 48-h post-treatment inoculation. Treatment × hour interactions were noted for IVDMD (in vitro dry matter digestibility) and IVNDFD (in vitro neutral detergent fibre digestibility) (P ≤ 0.05). More specifically, DFM inoculation increased (P ≤ 0.03) IVDMD at 24 h in four forages and increased 48-h IVDMD (P ≤ 0.02) in alfalfa hay, ryegrass, leucaena, and Mitchell grass hay, but opposite results were observed for Queensland bluegrass (P < 0.01). A 24- and 48-h IVNDFD increased following DFM inoculation (P ≤ 0.02) in five forage sources, but reduced for Queensland bluegrass (P < 0.01). When the forages were classified according to their quality, main treatment effects were detected for IVDMD (P ≤ 0.02) and IVNDFD (P < 0.01). In experiment 2, five common cereal grains were evaluated—high-density barley (82 g/100 mL), low-density barley (69 g/100 mL), corn, sorghum, and wheat—under the same treatments as in experiment 1. In vitro starch digestibility (IVSD) was evaluated at 6- and 12-h following treatment inoculation. Treatment × hour interactions were observed for starch digestibility in three out of five concentrate sources (P ≤ 0.001). Inoculation of DFM yielded greater 24-h starch digestibility for high-, low-density barley, and wheat (P ≤ 0.02), but also greater at 48 h in wheat (P < 0.0001). Moreover, mean starch digestibility improved for corn and sorghum inoculated with DFM (P < 0.01). Using a Bacillus-based DFM (B. licheniformis and B. subtilis) improved the mean in vitro DM and NDF digestibility of different forage sources of varying qualities (based on crude protein content). Similarly, IVSD was also greater following DFM inoculation, highlighting the potential of this probiotic to improve nutrient digestibility and utilization in the beef and dairy cattle herd.

Evaluation of the Quality Characteristics of Complementary Food from Whole Maize Fortified with Bambara Groundnut and Tiger Nut

Complementary foods produced from formulation of whole maize flour (WMF), maize flour supplemented with bambara groundnut and tiger nut flour (MBTF), maize flour supplemented with bambara groundnut flour (MBF) and maize flour supplemented with tiger nut flour (MTF) were evaluated for their quality characteristics. The results obtained showed that MTF was the most acceptable in taste (4.40 ± 0.70), consistency (4.10 ± 1.10) and aroma (4.30 ± 0.67). In moisture and ash contents, WMF recorded the highest mean scores of 9.10 ± 0.12% and 5.05 ± 0.10% respectively. Compared with WMF, MBF and MBTF, MTF had the highest mean scores in carbohydrate (53.62 ± 0.75%) and crude fibre (6.04 ± 0.69%). However, crude protein content was reportedly higher in MBF (32.13 ± 1.22%), while MBTF recorded the highest mean score in fat content (14.13 ± 0.23%). The in vitro protein digestibility (IVPD) and in vitro starch digestibility (IVSD) of the products were influenced by the inclusion of bambara groundnut flour; and the results showed that MBTF recorded the highest IVPD and IVSD at mean values of 73.00% and 70.50% respectively. The water absorption capacity of the products were relatively low; and is considered important for the transportation and extension of their shelf stability. The optimization of the protein digestibility and nutritional qualities of observed in the products indicated that bambara groundnuts and tiger nuts could find applications in a variety of complementary food products that are beneficial to infants; especially among rural dwellers and low-income individuals.

In vitro digestibility of gels from different starches: Relationship between kinetic parameters and microstructure

Starch performance along digestion is becoming of utmost importance owing to the extensive presence of starch in foods and its association to the foods glycaemic index. However, scarce information exists on the relationship between the digestibility of starch gels and their microstructure. The aim of the study was to identify the rate and degree of digestion of starch gels from different botanical sources and the impact of gels microstructure with the in vitro starch digestibility (IVSD) by fitting the hydrolysis kinetics. Starch gels from cereals, tubers, and pulses were structurally analyzed and subjected to a standardized oro-gastrointestinal IVSD. The gel microstructure was significantly different among starches. Cereal gels had thinner walls than tuber and pulses gels, and this discrimination was not evident in the area of the gel cavities. Starches hydrolysis was well fitted to a first-order kinetics model, except for rice starch gel. Potato and chickpea gels showed the slowest digestion, and in the case of potato gel some starch remained undigested at the end of the digestion. The amylose content of gels was correlated with starch hydrolysis rate. Moreover, starch gels with thinner walls and/or bigger cavities seems to facilitate the enzyme action, and therefore, the starch digestibility.

Effects of exogenous α-amylases, glucoamylases, and proteases on ruminal in vitro dry matter and starch digestibility, gas production, and volatile fatty acids of mature dent corn grain.

Two separate experiments were carried out to evaluate the effects of incremental doses of 10 exogenous endo-acting α-amylase and exo-acting glucoamylase; 1LAT (bacterial α-amylase), 2AK, 3AC, 4Cs4, 5Trga, 6Afuga, 7Fvga, and 10Tg (fungal α-amylases, glucoamylases, and α-glucosidase), 8Star and 9Syn (fungal amylase-mixtures; experiment 1) and three exogenous proteases; 11P14L, 12P7L, and 13P30L (bacterial proteases; experiment 2) on in vitro dry matter digestibility (IVDMD) and in vitro starch digestibility (IVSD) of mature dent corn grain using a batch culture system. Incremental doses of the exogenous enzymes (0, 0.25, 0.50, 0.75, and 1.00 mg/g of dried substrate) were applied directly to the substrate (0.5 g of ground corn, 4 mm) in sextuplicate (experiment 1) or quadruplicate (experiment 2) within F57 filter bags, which were incubated at 39 °C in buffered rumen fluid for 7 h. Rumen fluid was collected 2–3 h after the morning feeding from three lactating dairy cows and pooled. Cows were consuming a midlactation total mixed ration (TMR; 1.60 Mcal/kg DM and 15.4%; net energy of lactation and crude protein, respectively). Three independent runs were carried out for each experiment. Data were analyzed as a randomized complete block design using run as the blocking factor. Dose was used as a fixed factor while run was considered a random factor. Linear, quadratic, and cubic orthogonal contrasts were also tested. In experiment 1, enzymes 2AK, 3AC, and 10Tg did not increase (P > 0.10) IVDMD and IVSD, whereas 0.25 mg of enzymes 1LAT, 5Trga, and 8Star increased (P < 0.01) IVDMD by 23%, 47%, and 62% and IVSD by 35%, 41%, and 58%, respectively, compared with the control. Enzymes 4Cs4, 6Afuga, 7Fvga, and 9Syn linearly increased IVDMD and IVSD (P < 0.01). Greatest increases in IVDMD (82.9%) and IVSD (85.9%) resulted with 1 mg of 6Afuga compared to control. In experiment 2, the lowest dose of exogenous proteases 11P14L and 12P7L increased (P < 0.01) IVDMD by 98% and 87% and IVSD by 57% and 64%, respectively, whereas the highest dose of 13P30L increased (P = 0.02) IVDMD by 44.8% and IVSD by 30%, relative to the control. In conclusion, IVSD and IVDMD were increased by one α-amylase, certain glucoamylases, and all proteases tested, with the glucoamylase 6Afuga in experiment 1 and the neutral protease 12P7L in experiment 2, increasing IVDMD and IVSD to the greater extents. Future in vivo studies are required to validate these findings before these enzyme additives can be recommended for improving the digestibility of mature dent corn grain.

Impact of Extrusion Temperature on In Vitro Digestibility and Pasting Properties of Pea Flour.

Pea flour was extruded at 50, 70, and 90°C. The in vitro digestibility and characteristics of native and extruded pea flour were investigated. The in vitro starch digestibility (IVSD) and in vitro protein digestibility (IVPD) of the extruded pea flour were higher than those of the native pea flour and increased with increasing extrusion temperature from 50 to 90°C. The rapidly digestible starch increased to 28.34% at 90°C, the highest slowly digestible starch (SDS) content was 22.70% at 50°C, and resistant starch content decreased to 4.71% at 90°C. The IVPD increased from 80.94% relative to the native pea flour to 90.21% at 90°C. Improved swelling power enabled the extruded pea flour to exhibit better performance and higher breakdown viscosity and lower setback viscosity than the native pea flour demonstrated that extrusion reduced the thermal stability and retrogradation tendency. Increasing extrusion temperatures greatly reduced the relative crystallinity (based on X-ray diffraction analysis) from 32.69% relative to the native pea flour to 9.76% at 90°C. Extrusion treatment also reduced β-sheet content (based on Fourier transform infrared spectroscopy analysis) from 36.40% relative to the native pea flour to 31.79% at 90°C. IVPD and IVSD improved, and the SDS content increased at 50°C and 70°C, thereby indicating that extruded pea flour can be applied to healthy food products.

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

SummaryThe 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.

Nutritional quality of raw and cooked flours of a high β-glucan sorghum inbred line

This study investigated the protein fractions, in vitro protein digestibility (IVPD), in vitro starch digestibility (IVSD), antinutritional factors, hydrolysis index (HI), and estimated glycemic index (eGI) of the raw and cooked flours of a new sorghum inbred line (high β-glucan type I non-tannin sorghum) compared to two popular Sudanese sorghum cultivars (low β-glucan type 1 non-tannin and type II tannin sorghums). Significant differences (P < 0.05) were observed in protein fractions, antinutritional factors, IVPD, IVSD, rapidly digestible starch (RDS), resistant starch (RS), HI, and eGI. Low β-glucan type II tannin sorghum showed the highest antinutritional factors and RS values, whereas high β-glucan type I non-tannin and low β-glucan type 1 non-tannin sorghum cultivars showed the least values (P < 0.05). Low β-glucan type 1 non-tannin sorghum had the highest IVPD, RDS, HI, and eGI values. Cooking significantly (P < 0.05) reduced the protein fractions, antinutritional factors, IVPD, and RS and increased the IVSD, RDS, HI, and eGI of sorghums. Based on low eGI of high β-glucan type I non-tannin sorghum cultivar, it can be considered a low glycemic index sorghum and could thus be the best choice for diabetic people.

Impact of Feed Moisture on Microstructure, Crystallinity, Pasting, Physico-Functional Properties and In Vitro Digestibility of Twin-Screw Extruded Corn and Potato Starches.

The effect of extrusion feed moisture (FM) on the microstructure, pasting, physico-functional properties and in vitro starch digestibility (IVSD) of corn and potato starches was investigated using scanning electron microscopy (SEM), X-ray diffractometry and a rapid visco-analyser. Starches were extruded at 14, 18 and 22% FM with an extrusion temperature of 100°C and a screw speed of 100rpm. Extruded starches showed lower L* (lightness) values and higher a* and b* values than native starches. An increase in FM increased the L* values and decreased the a* and b* values of extruded starches. Extrusion resulted in complete destruction and reduced crystallinity of the starch structure. Extruded starches showed a lower water absorption index (WAI), peak viscosity (PV), final viscosity (FV), breakdown viscosity (BDV) and setback viscosity (SBV) with a higher water solubility index (WSI) and IVSD than native starches. FM showed a negative correlation with the WSI and IVSD and a positive correlation with the WAI, PV, FV, BDV and SBV of extruded starches.

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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 65.9g 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.

Influence of health based ingredient and its hydrocolloid blends on noodle processing

Blends were prepared with different levels of chickpea flour (CF) and durum semolina (0–60 %) and were utilized for understanding their influence on product quality. Proximate analysis and rheological characterization of blends were carried out. Noodles were developed and subjected to different physico-chemical, nutritional, cooking quality and sensory analysis, scanning electron microscopy (SEM). Optimized noodles on the basis of its sensory and cooking quality characteristics were improved with different hydrocolloids. Rheological studies revealed that with the increase in the CF content, Farinograph water absorption and dough stability decreased; simultaneously increase in dough development time. Maximum over pressure and curve configuration decreased with increase in CF. Based on the sensory and cooking loss of noodles 50 % formulation was improved with hydrocolloids. Noodles cooking loss reduced to 5.9 % with the addition of guar gum. Sensory scores for the noodles were above 8 in 15 cm scale. Colour value showed an increase in ‘b’ value, indicating increase in yellowness of samples. Texture of noodles became firm with the addition of CF. IVSD (In vitro starch digestibility) reduced from 71 to 29 %. There was a network like formation due to hydrocolloids was observed in SEM, which is the reason for slow release of glucose. Thus, can be used as substitution in noodles and can be included in the diet of malnutritious and diabetic population.

A study on noodle dough rheology and product quality characteristics of fresh and dried noodles as influenced by low glycemic index ingredient

Low Glycemic Index (LGI) foods help to maintain blood glucose level in diabetic individuals. Pea flour (PF) is known to be one of LGI ingredients used in the food industry. To assess the influence of PF in noodle processing, thermally processed pea flour was incorporated at 20% and 40% in the preparation of noodles using Lab scale Noodle Making Machine. Evaluation for Physico-chemical, rheological and noodle making characteristics, in vitro starch digestibility (IVSD) and microstructure of noodles were carried out. Cooking quality did not show any significant difference among the samples, with solid leach out ranging from 6.7 to 7.2% against control (6.5%). Colour measurement showed the presence of greenish colour in PF incorporated samples. Texture was firmer in fresh noodles (FN) (5.52 Newton (N), 6.00N) and dried noodles (DN) (7.60N, 7.86N) compared to control (4.38N-FN, 6.88N-DN). Sensory analysis of noodles revealed that the samples (FN, DN) were acceptable at 20% and 40% levels with overall quality score (>8.5). In vitro analysis revealed that with increase in PF content there was a significant decrease in the availability of glucose in DN followed by FN compared to control. Overall RDS was reduced and SDS was increased in 40% PF incorporated FN. Scanning-electron microscopy revealed the presence of fiber matrix around the starch granules.

Effect of natural and Lactobacillus plantarum fermentation on in-vitro protein and starch digestibilities of sorghum flour

Sorghum flour was either naturally fermented or inoculated by Lactobacillus plantarum at 37 1C for 36 h. Changes in bacteria, pH, acidity, protein, in-vitro protein digestibility (IVPD), starch content and in-vitro starch digestibility (IVSD) were monitored every 4 h. Pasting properties were carried out only in the native sorghum flour, and two types of fermented flour with highest improved IVPD and IVSD. Results showed that both fermentation types increased total bacteria by 5 log, lactic acid bacteria (LAB) by 5 log, and proteolytic bacteria by 2-3 log cycles. The pH decreased from 5 to 3 with the increased of titratable acidity. Natural and L. plantarum fermentations for 36 h improved IVPD by 46.89% and 92.08%, respectively, and increased IVSD by 71.48% and 65.63%, respectively. The highest IVSD enhancement (78.69%) was shown by L. plantarum for 28 h. Fermentation decreased gelatinization temperature (GT), increased peak viscosity (PV) and hot paste viscosity (HPV). The greatest improved viscosities were shown by L. plantarum.

Effect of germination periods and hydrothermal treatments on in vitro protein and starch digestibility of germinated legumes

Germination of legumes followed by hydrothermal treatments is an effective mean of improving nutritive value of legumes. The protein content of mungbean, chickpea and cowpea increased by 9-11, 11-16 and 8-11% after germination. A significant (p ≤ 0.05) decrease in protein content was observed on pressure cooking and microwaving in all three legumes. The carbohydrates decreased by 1 to 3% during soaking and 2 to 6% during germination. A significant (p ≤ 0.05) improvement in in vitro protein digestibility (IVPD) was observed after soaking as well as after three germination periods. Germination resulted in an increase in IVPD from 15 to 25% in mungbean, 6 to 17% in chickpea and 6 to 17% in cowpea. A significant (p ≤ 0.05) increase in IVPD was observed when raw sprouts of three legumes were subjected to pressure cooking and microwaving. In vitro starch digestibility (IVSD) increased significantly (p ≤ 0.05) after germination, the percent increase being 8 to 12% in mungbean, 9 to 11% in chickpea and 10 to 13% in cowpea. The duration of germination had significant (p ≤ 0.05) effect on IVSD. A significant (p ≤ 0.05) improvement in IVSD was observed when legume sprouts were subjected to pressure cooking and microwave cooking.

Changes in Quality Characteristics of Jeungpyun containing different Levels of Malt Extract during Storage

This study evaluated the effects of different levels of malt extract on the hardness, moisture, water soluble starch (WSS) contents, and in vitro starch digestibility (IVSD) of Jeungpyun during storage at room temperature () and refrigeration temperature (). Resistant starch (RS) and soluble starch (non-RS) contents were also evaluated. During storage at both temperatures, hardness increased in Jeungpyuns with the malt extract-added Jeungpyun groups (malt-added Jeungpyuns) exhibiting lower hardness than the control. The rate of retrogradation was faster upon storage at refrigeration temperature. Moisture and WSS contents as well as IVSD of Jeungpyuns decreased, whereas these levels were higher in malt-added Jeungpyuns compared to control. Storage increased RS contents in Jeungpyuns stored for up to 4 days, particularly at , whereas there was a decrease in RS content after 7 days of storage. However, RS content was lower in malt-added Jeungpyuns compared to control. Soluble starch (SS) contents of Jeungpyuns decreased. However, SS content was higher in malt-added Jeungpyuns than that of control. The reduced hardness and RS content as well as the rate of increase in other parameters of malt-added Jeungpyuns were dependent on the concentration of malt extract. These results reveal that addition of malt extract delayed retrogradation of Jeungpyun, whereas retrogradation possibly increased the content of RS during storage at both temperatures, however, that of RS decreased with increasing level of malt extract, suggesting that the level of malt extract as well as the storage conditions are important for obtaining acceptable texture and retaining the RS content of Jeungpyun, which is known to possess physiological activity.

Pre-treatment effect on the nutritional and functional properties of selected cassava-based composite flours

Abstract The low protein and lack of gluten in cassava ( Manihot esculenta Crantz) are disadvantageous for its use for product development and is overcome through the use of composite flours incorporating cereal and/or legume flours. The functionality and nutritional attributes of cassava flour were altered in the present study by pre-treatment with termamyl and green gram amylase, pre-gelatinization and subsequent blending with cereals, legumes, bran sources etc. Malting of cassava flour with termamyl followed by pre-gelatinization reduced the starch and increased the sugar content of the mixes. Pre-gelatinization had little effect on the crude protein of the mixes; nevertheless, the fat content was higher by 0.15–1.0 units. Energy content was around 1176 and 1217 KJ/100 g for the rice bran added mixes from malted cassava, which slightly increased in the respective pre-gelatinized cassava mixes. The peak viscosity of termamyl treated cassava-based flour mixes was much lower than the respective gram amylase based mixes, indicating that the latter had much less amylolytic activity than termamyl and pre-gelatinization further reduced the viscosity. The very low viscosity for the enzyme treated cassava-based mixes was due to the inability for retrogradation of the hydrolyzed starch. Significant improvement in in vitro starch digestibility (IVSD) (enhancement by 5.0–16.0 units in termamyl treatment vs 5.0–9.0 units in gram amylase treatment) was observed for the pre-gelatinized mixes. Lowest IVSD (25–29 units) was for the two bran based mixes, suggesting its use in the nutrition therapy for controlling obesity linked diseases. Industrial relevance With the development in human society, the incidence of chronic diseases like diabetes, cancer, cardiovascular problems and conditions like obesity contributing to several diseases is on the increase. This has led to an increasing awareness and research efforts on the development of functional foods, pharmafoods etc, which have wide potential application in medical nutrition therapy. The present work aims at improving the nutritional and functional attributes of cassava through fortification with cereal and/ or legume flours, bran sources etc. and through pre- treatment with enzymes to improve the functionality and reduce the energy content. The study led to the development of cassava based composite flours with low starch digestibility, high protein content and low energy content which could be effectively utilized for developing designer foods for obese and diabetic people. Enhanced digestibility of pre- gelatinized malted flours from cassava finds potential application for the development of foods for geriatric and convalescent people.