Water Solubility Index Values Research Articles

Effect of Single and Dual Modifications on the Physicochemical Properties of Sago Starch Modified by Ozonation and Acetylation

Abstract Dual-step starch modification is an effort to eliminate weaknesses in single-step modification. This research aims to study the effect of single-step or dual-step modification methods on the physicochemical properties of sago starch. The single step consists of ozonation (Oz) and acetylation (As), while the dual step (sequentially), namely ozonation-acetylation (Oz-As) and acetylation-ozonation (As-Oz). The physiochemical responses measured were water content, carbonyl content, carboxyl content, acetyl content, water solubility index (WSI), water absorption index (WAI), and color. Ozonation causes the formation of carbonyl and carboxyl groups, and the modification process certainly causes the addition of carbonyl and carboxyl groups both in single step and dual-step. Acetylation causes higher acetyl group values in either single-step (As) or dual step (Oz-As and As-Oz) compared to original sago starch. There was a significant difference between the single and dual steps in the WSI and WAI values. The characteristics of Ozonated-acetylated (Oz-As) modified sago showed starch the highest WSI and WAI results. The water content in single-step modified sago starch compared to native sago starch has no significant difference in water content, whereas the dual-step modified sago starch has a higher water content than the native one.

Talc and calcium carbonate inclusions in direct expanded pea starch extrudates exhibit different behavior under increasing screw speeds.

The ability to modulate direct expanded product structures improves the versatility and range of product applications. The effect of nucleating agents, namely, talc and calcium carbonate (CC), on the expansion characteristics of pea starch extrudates as impacted by screw speed was explored. Pea starch blends with increasing levels of nucleating agents (0.25%, 1%, and 2%) at 18% moisture (w.b.) were extruded across a range of screw speeds (150, 250, 350, and 450rpm). The water absorption index, water solubility index (WSI), expansion ratio (ER), unit density, and cell count were determined to evaluate the performance of nucleating agents. The nucleating efficiency of CC, as assessed by cell count, improved with increasing screw speeds. In contrast, the nucleating efficiency of talc was influenced by inclusion levels irrespective of screw speed. ER values ranged from 2.10 to 2.88, where higher nucleating agent inclusions and screw speeds corresponded with lower ER values. Increased nucleating agents and screw speeds corresponded to higher WSI values suggesting the nucleating agents promoted starch degradation. The nucleating agents appeared to promote flow instabilities indicated upon assessment of the extrudate surface. PRACTICAL APPLICATION: This study provides helpful information on the expanded extrudate structure of pea starch as influenced by screw speed and nucleating agents. These findings may help the food industry select processing parameters and appropriate nucleating agent inclusion levels when producing new expanded products with unique textures.

Physico-Chemical Characteristics of Novel Analog Rice from Fermented Sorghum Flour by Rhizopus oligosporus and Soybean Flour

The need for food in the world is currently increasing, one of high consumption is rice. Analog rice is one of the products for rice substitute consumption to meet staple food with better nutritional value. In this research, the production of analog rice was made from fermented sorghum using Rhizopus oligosporus which has been studied previously with the addition of soybean flour fortification. Raw materials of sorghum grain were fermented using Rhizopus oligosporus to reduce tannin levels of sorghum and the addition of fortified soybean flour aims to increase the nutrition of analog rice. Analog rice production is carried out using the extrusion method with fermented sorghum flour with fortified soybean flour in a ratio of 0 to 50%. Nutritional value of analog rice (carbohydrates, protein, fat, fiber, minerals, and water), morphology, water adsorption index (WAI), water solubility index (WSI), hydrophilicity, and consumer acceptance were characterized. The best nutritional of analog rice produced was obtained from the combination of 50% sorghum (red or white sorghum) and 50% soybean flour, which contained carbohydrates, protein, fat, and fiber of 58.29%, 17.07%, 14.47%, and 7.43% respectively. The increasing portion fortified of soybean flour was reduced the WAI and increased the density of the analog rice structure. These characteristics are friendly to diabetic patients since they are rich in carbohydrates, protein, and fiber. On the other hand, this analog rice has the potential to be consumed as a main food ingredient to replace paddy rice and develop to staple food. Moreover, the insignificant effect of the WSI value and hydrophilicity of the analog rice were observed. However, adding soybean flour as a substitute for analog rice was less attractive to consumers than analog rice without substitutes.

Factors Affecting the Starch Extraction from Jackfruit Seed (Artocarpus heterophyllus L.)

The study was conducted to investigate some factors affecting the starch extraction from jackfruit seeds (JS), including: Jackfruit seed drying temperature, extraction time and ratio of water to jackfruit seed flour (JSF). The JS were dried at various temperatures (50, 60 and 70oC) before grinding into flour. Starch was extracted in 4 levels of time (5, 6, 7 and 8 hours) interacted with 4 ratios of water to JSF (10, 15, 20 and 25 times, v/w). The efficiency of the extraction process was evaluated through the yield and the physicochemical properties of JSS, such as starch content, the color (L value and browning index - BI), water absorption index (WAI), water solubility index (WSI) and swelling power (SP); the scanning electron microscopy (SEM) and the average particle diameter (APD). The drying temperature of 60oC is considered suitable for obtaining good flour for performing starch extraction. Starch extraction from the JSF was carried out with the ratio of water to JSF of 15 times (v/w) for 6 hours at ambient temperature. The yield was 44.96?0.29%; the starch content was 92.06?0.48%. The JSS exhibited the values of WAI, WSI and SP in range of from other starches. The APD of JSS is 6.90–8.50 µm and is classified as small granules. All physicochemical properties as well as the APD of JSS were interrelated. These results showed that the extraction is high yield. The extracted JSS has high starch content and suitable physicochemical properties. When purified effectively, it has the potential to become food or effective complementary ingredients in the development of functional food products.

Mechanism of feed moisture levels in extrusion treatment to improve the instant properties of Chinese yam (Dioscorea opposita Thunb.) flour

Extruded yam flour was prepared at different feed moisture to improve its instant properties. The water solubility index (WSI) and water absorption index (WAI) were used to compare the instant properties of yam flour. Their chemical compositions, particle size distribution, crystalline structure, and microscopic forms were also analyzed to assess the effects of feed moisture on the instant properties of yam flour. We found that extrusion significantly improved the instant properties of yam flour, while the WSI value increased from 29.50% to 71.86% and the WAI value decreased from 387.88% to 228.06% with decreased feed moisture. Extrusion led to the degradation of total starch and amylopectin, and the contents of soluble substances increased markedly. Extrusion destroyed the granular and crystalline structures, which were reconstituted as amylose–lipid complexes with a significant decrease in relative crystallinity. Increasing the feed moisture was beneficial to the flow and color retention, while lower feed moisture was more favorable to enhance the instant properties.

Effect of extrusion parameters on physical and functional quality of soy protein enriched maize based extruded snack

The effect of extrusion parameters like barrel temperature (100-150°C), screw speed (110-350 rpm) and feed moisture content (12-20% wb) on product quality of extruded products prepared from composite mixture was performed. Central composite rotatable design was used to frame the experiment and statistically analyzed the data. The effect of parameters on expansion ratio (ER), bulk density (BD), hardness (H), crispness (Cr), water absorption index (WAI) and water solubility index (WSI) of extruded products were investigated and found significantly. The feed moisture had positive effect on BD, hardness and WAI whereas negative effect on ER, crispness and WSI of the extruded products. The barrel temperature and screw speed had negative effect on BD, hardness and WAI whereas reverse effect on ER, crispness and WSI. The developed models for all the product qualities were significant at 1% level. ER, BD, hardness, crispness, WAI and WSI values of extruded products was ranged from 2.017–3.391, 0.13–0.28 g/cm3, 12.43–19.04 N, 10–25 fractures, 5.76–7.25 g/g and 12.76–20.97%, respectively. The higher expansion ratio, crispness and WAI along with lower bulk density, hardness and WSI of extruded product were found at the process parameters combination of feed moisture 14% (wb), barrel temperature 110°C and screw speed 301 rpm.

ENHANCED BIOACCESSIBILITY BY EXTRUSION PROCESS AND QUALITY PARAMETERS OF RED PEPPER PULP ADDED EXTRUDATES

Only bioaccessible nutrients can be absorbed and used by the body to contribute to health. The study aimed to investigate the effect of extrusion on the in vitro bioaccessibility of β-cryptoxanthin and zeaxanthin in extrudates supplemented with red pepper pulp. Corn grits mixed with red pepper pulp were extruded. β-cryptoxanthin, zeaxanthin, and total phenolic content with antioxidant activity analysis were conducted on the feed and extruded samples. Quality parameters of the corn grit extrudates, prepared with and without red pepper pulp, were also investigated. The extrusion process significantly increased the in vitro bioaccesibiliy of zeaxanthin, but no statistically significant difference was observed for β-cryptoxanthin. After the extrusion process, total phenolic, β-cryptoxanthin, and zeaxanthin contents with antioxidant activity were lower. Physical quality parameters such as hardness, expansion, and water absorption with water solubility index values were not affected by the addition of red pepper meal. The porosity decreased, and hence the bulk density increased. Sensory analysis showed that the preference scores of the panelists for the samples with the addition of red pepper meal were not different from the control. This study showed that the extrusion process could improve the in vitro bioaccessibility of functional components. Additionally, red pepper pulp can be added as a functional ingredient to extrudates to develop new products without changing consumer preferences.

Elastic gels based on flaxseed gum with konjac glucomannan and agar.

In this study, we prepared hydrocolloid gels in which flaxseed gum (FSG), konjac glucomannan (KGM), and agar (AG) were blended in different ratios for use as a viscoelastic food. The prepared hydrogels' physicochemical properties were analyzed concerning their water solubility index (WSI), swelling power (SL), frequency sweep results, and microstructures. As the FSG ratio decreased, the WSI value of the compound gel tended to increase. However, it showed a tendency to have a relatively high SP value and a low tan δ value according to a specific KGM/FSG/AG mixing ratios (8:2:1.5 and 6:4:1.5). Through microstructure analysis, the FKA821.5 sample showed a relatively small, monodispersed gel building structure, correlated with the rheological results. In conclusion, the FKA821.5 gel was determined to have good water retention capacity and high structural strength. These results are expected to increase the applicability of FSG-based gelling agents in the food industry.

Defined shear and heat treatment of apple pomace: impact on dietary fiber structures and functional properties

Food by-products can be modified by extrusion processing. However, the impact of thermal and mechanical stress, respectively, on the structure and thus functional properties of dietary fiber-rich food by-products is still unknown. In the extrusion process, thermal and mechanical stress are coupled, not constant, and difficult to measure or calculate. Thus, their influence on structural changes and functional properties cannot be evaluated separately. In this work, a specific shear cell, denoted by closed cavity rheometer, was used to treat apple pomace with defined thermal and/or mechanical stress. Dietary fiber composition and fiber polysaccharide structures appeared to be more susceptible to high temperatures than mechanical stress. With increasing temperature (and mechanical stress) soluble and low-molecular-weight soluble dietary fiber contents increased, whereas insoluble fiber contents decreased. Arabinans as rhamnogalacturonan type I polysaccharides and galacturonic acid containing pectic polysaccharides were identified as being most susceptible to degradation under these conditions. Furthermore, the defined treatment affected the functional properties. Although changes in the water solubility index (WSI) and/or the water absorption index (WAI) were not detected up to 90 °C, WSI and WAI decreased significantly at a treatment temperature of 120 °C. However, at very high temperatures (160 °C), WSI and WAI increased. The application of shear and longer treatment times resulted in higher WSI values and complex viscosities as compared to low shear stress.Graphic abstract

Evaluation of the physicochemical properties of third-generation snacks made from blue corn, black beans, and sweet chard produced by extrusion

The effects of extrusion on the physicochemical properties of a mixture of blue corn, black bean, and sweet chard (MBBC) used for indirectly extruded snacks (PECB) and microwave-expanded snacks (MEPM) were evaluated. MBBC was conditioned at moisture content (MC) of 22.2–35.7%, extruded at temperature (ET) of 102–142 °C, and screw speed (SP) in the range of 96–171 rpm. The water absorption index (WAI), water solubility index (WSI), expansion index (EI), final viscosity (FV), setback values, total anthocyanin (TAC), hardness, FT-IR, X-ray analysis, and microstructure were evaluated. TAC increased with the reduction of ET of PECB and MEPM. Reductions in MC and increases in SP caused an increase in EI, WAI, and WSI, while PV and setback values showed contrasting behaviors. Micrographs revealed that extrusion destroys the granular structure of starch EMCB-generated. FT-IR showed that extruded samples increased the intensity of bands at 994 and 1016 cm−1 in comparison to raw starch, and can be observed V-type diffraction pattern. The predicted optimal conditions were obtained at 133 rpm, 25% MC, and 122 °C. Under these conditions, extruded products had greater retention of anthocyanins (34%) with adequate rheological parameters, which resulted in a maximum expansion of the extrudates.

Nutritional characterization and food value addition properties of dehydrated spinach powder.

This study aimed at investigating the physicochemical and bread‐making features of dehydrated spinach. Physicochemical composition of spinach powder was compared with wheat flour and the effect of spinach powder supplementation on the nutritional composition, dough rheology, and quality attributes of chapatti were assessed. The results suggested spinach powder to be holding 8.2% crude fiber, 19.2% protein, 1,304 mg/100g calcium, and 40.4 mg/100g iron. Spinach powder indicated significantly increased values for hygroscopicity, swelling power, and water solubility index values, that is, 6.4%, 7.1 g/g, and 4.2%, respectively, when compared with wheat flour. Supplementation of spinach powder in wheat flour at 20% substitution level significantly reduced dough development properties including water absorption, dough stability, and peak dough development time. Color measurements of baked chapatti indicated a significant reduction in L*, a*, and chroma values with increasing the level of spinach powder supplementation; however, sensory profiling confirmed that supplementation of spinach powder at 7.5% had an optimum effect on the overall acceptability of the baked product. The results further suggested that replacing wheat flour with spinach powder (5%–7.5%, w/w) in baked products could be a viable dietary approach to enhance the optimum supply of micronutrients and to combat micronutrient deficiencies among various population segments.

Effects of superfine grinding on micromeritic properties of Eucommia ulmoides Oliv. leaves

Effects of regular grinding and superfine grinding on the micromeritic properties of Eucommia ulmoides leaves were investigated. Coarse powder 1 (5732 nm), 2 (4784.67 nm), 3 (4133.67 nm), 4 (2119 nm) were prepared by regular grinding. Superfine powder 5 (1310.67 nm) was prepared by superfine grinding, all the particle sizes presented normal distribution. Results showed that Eucommia ulmoides leaf powders have smaller size, greater bulk density and smaller angle of repose. The water solubility index values, water holding capacity value and oil binding capacity value were significantly improved as the size decreases. Furthermore, biological microscopy revealed the surface morphology of five powders. FT-IR analysis showed the nature of Eucommia ulmoides leaves unchanged. These results showed that the physicochemical and functional properties of Eucommia ulmoides leaves can be improved by superfine grinding, which would be more suitable for the development of functional compounds than native Eucommia ulmoides leaves.

Pea starch exhibits good expansion characteristics under relatively lower temperatures during extrusion cooking.

Extrusion processing characteristics of pea starch were studied as impacted by various extrusion cooking processing variables, including, moisture content (15%, 17.5%, and 20% w.b.), temperature (120, 135, and 150 °C), and screw speed (150, 200, and 250rpm), in a co-rotating twin-screw extruder. Physicochemical properties such as radial expansion ratio (ER), unit density (UD), water absorption index (WAI), and water solubility index (WSI) were measured. ER of the extrudates ranged between 2.52 and 3.63. These values of ER were significantly high, although relatively lower compared to the highest values reported in the literature for corn and rice extrudates. The UD values for all the extrudates ranged from 0.12 to 0.35g/cm3 , WAI, and WSI values ranged from 10.98 to 12.10g/g and from 0.12% to 7.73%, respectively. Both screw speed and moisture content had significant impacts on the ER (P <0.01). The highest ER was observed for the extrusion cooking conditions of the lowest moisture content level (15%), lowest barrel temperature (120 °C), and lowest screw speed (150rpm). The cross-sectional microstructure of the extrudates showed that the samples with a high ER had thick and elongated pores. The results of this study indicate that pea starch is a viable ingredient for making puffed extruded products. PRACTICAL APPLICATION: The food industry can utilize the information generated from this study in the development of extruded expanded food products with pea starch. The specific information related to process conditions can assist the food industry in determining the ideal conditions for extrusion cooking in the production.

Optimization of maize-millet based soy fortified composite flour for preparation of RTE extruded products using D-optimal mixture design.

Formulation of composite flour comprising of maize (MF), finger millet (FM), defatted soy (DS) and elephant foot yam (YP) was carried out for the preparation of extruded product. The proportion of three major ingredients was varied as maize: 40-55%, finger millet: 20-30%, defatted soy: 10-25% and that of YP was kept constant as 10%. In all 16 experiments were conducted by D-optimal mixture design keeping the upper and lower values of ingredients in the range given above. Extruded products were developed by using twin screw extruder (BTPL lab model) at barrel temperature 100°C, screw speed 300rpm and feed moisture content 15% (wb). Physical and functional properties like expansion ratio (ER), bulk density (BD), hardness, water absorption index (WAI) and water solubility index (WSI) of extruded products were analyzed. Composite flour was optimized on the basis of physical and functional properties of extruded products. The values of ER, BD, hardness, WAI and WSI of extruded products were in the range of 2.42-3.30, 0.14-0.26gcm-3, 11.15-18.67N, 5.57-6.87gg-1 and 14.42-19.95%, respectively. Variations in proportion of ingredients in the composite blend significantly affected ER, BD, hardness, WAI and WSI of the product. The regression models for ER, BD, hardness, WAI and WSI were developed to explain the effect of ingredients on the response variables. A blend of ingredients in the ratio of 40:30:20:10 (MF:FM:DS:YP) was found to be optimum with a desirability function of 0.82 which resulted extrudate attributes of ER 3.29, BD 0.14gcm-3, hardness 11.94N, WAI 6.13gg-1 and WSI 17.07%.

Physicochemical Properties and Resistant Starch Content of Corn Tortilla Flours Refrigerated at Different Storage Times.

The tortilla is a foodstuff that has a short shelf-life, causing great losses to the industry. The objective of this work was to evaluate, for the first time, the physicochemical properties and resistant starch (RS) content of flours. These were obtained from nixtamalized corn tortillas made with traditional and industrial (commercial) methods, stored at 4 °C for 7, 15, and 30 days. The flours were characterized by measuring particle size distribution, color, water absorption index (WAI), water solubility index (WSI), viscosity, calcium, and RS content. Additionally, chemical proximate analysis, scanning electron microscopy (SEM), and thermal analysis were conducted. Storage at 4 °C increased the friability of tortillas and shifted the particle size distribution toward a greater content of coarse particles in corn tortilla flours. The commercial corn tortilla flours showed higher WAI and WSI values than the traditional corn tortilla flours. On the other hand, the traditional corn tortilla flours exhibited higher RS content values than commercial corn tortilla flours as well as peak viscosity. X-ray diffractograms revealed the presence of amylose-lipid complexes (RS5) in experimental samples. The thermograms evidenced three endotherms corresponding to corn starch gelatinization and melting of type I and type II amylose–lipid complexes.

Effect of Acheta domesticus (house cricket) addition on protein content, colour, texture, and extrusion parameters of extruded products

Acheta domesticus is one of the most promising reared insects because of their attractive nutritional profile and lower feed conversion ratio than other animals. Hence, it has potential to increase the nutritional value of food products. The aim of this study was to evaluate the effects of enrichment, with different quantities of Acheta domesticus powder, on protein content, physicochemical properties, and extrusion parameters of extruded corn snacks. Extrudate characteristic parameters were fitted against Acheta domesticus concentration and these represented equations were very closed with the experimental data according the obtained adjusted R2. Using Acheta domesticus powder increased the protein content of extrudates showing suitable extrusion parameters. Extruded snack enrichment with 12.5 and 15% of Acheta domesticus powder are foods classed as “source of protein” according to European law n. 1924/2006. However, high Acheta domesticus concentration in mixtures resulted in low expansion and less crunchy extrudates, but low risk of molecular damage by molecules solubilised in water, gave more stability due to lower values of water solubility index. To maintain typical extrudate parameters, the use of 7.5% Acheta domesticus is recommended for extruded snack mixtures.

Effect of Roasting Time and Cryogenic Milling on the Physicochemical Characteristics of Dried Ginseng Powder.

This study aimed to evaluate the effect of reduced particle size of ginseng by roasting and cryogenic milling on increasing its water solubility and physiological activity. The samples were roasted for different times (9–21 min) and generated in different sizes (10–50, and >50 μm). All roasted samples revealed significantly smaller particle sizes than did non-roasted samples, based on Sauter mean diameter (D [3,2], p < 0.05). Furthermore, the particle sizes of roasted samples decreased until roasting up to 15 min. In terms of the water solubility index (WSI), antioxidant activity, total polyphenol content (TPC), and total polysaccharides according to particle size, 10–20 μm-sized samples showed the highest values when compared with >50 μm-sized samples. Based on roasting time, WSI values of all samples roasted for up to 15 min were higher than those of the control (not roasted) (p < 0.05). Antioxidant activity and TPC also increased with increasing roasting time. Total polysaccharide content was the highest upon roasting for 15 min, except for the 10–20 μm sample. Ginsenoside content of roasted samples >20 μm size was higher than that of the control (not roasted) except after 15 min of roasting. Therefore, roasting and cryogenic milling are effective in producing ginseng root powder.

Effect of Pregelatinization and Retrogradation on Some Physicochemical Changes of Wheat-Potato Starches

The freezable (FW) and unfreezable water (UFW) contents of wheat and potato starches and their physically modified forms [pregelatinized (PGS) and retrograded (RS)] were analyzed by Differential Scanning Calorimetry (DSC) at various hydration levels (25, 35, 45, 55, 65, 75 and 85%). In all the starch samples, the UFW content increased with increasing hydration level. Potato starch samples (native, pregelatinized and retrograded) had higher UFW contents than wheat starch samples at all hydration levels. Similarly, with the increase of hydration level in all starch samples, onset (To), peak (Tp) and endset (Te) temperatures of the peaks also increased. It was obtained that physical modifications in starches had significant effects (P<0.05) on water absorption index (WAI) and water solubility index (WSI) of starch samples. The highest WAI (10.51) and WSI (2.31) values were determined in pregelatinized potato starches. Rapid Visco Analyzer (RVA) profiles revealed that physically modified starches had higher viscosity values than native starches. The results clearly showed that pregelatinization and retrogradation had positive effects on the physicochemical properties studied.

Response surface methodology for evaluation of the effects of screw speed, feed moisture and xanthan gum level on functional and physical properties of corn half products

Effects of screw speed (100–300 rpm), feed moisture (37–47%) and xanthan gum (XG) level (0–1%) on the functional and physical properties of corn half products were investigated and optimized by using three-factor and three-level Box-Behnken design (BBD) under response surface methodology (RSM). Response variables are water absorption index (WAI), water solubility index (WSI), degree of gelatinization (DG), water activity (aw), specific volume and color properties of extrudates. Increased screw speed decreased WAI and aw values and increased WSI values significantly. Specific volume of half products was low for all extrusion combinations and negative correlated with screw speed, feed moisture and XG level. Lightness and yellowness of half products were increased with increases in screw speed, feed moisture and XG level. Low DG for all half products was obtained (46.33–63.36%) because of temperature under 100 °C in last two zones in extruder. Desirability function approach was used to find the optimum extrusion conditions. The optimized combinations of extrusion conditions were found 300 rpm screw speed, 47% feed moisture and 0.44% XG content with a desirability value of 0.991. No significant difference was found between experimental data and predicted values.

Use of blackcurrant and chokeberry press residue in snack products

Abstract Fruit and vegetable processing by-products, undervalued until recently, are rich sources of nutrients. This study investigated properties of extruded corn puffs with addition (5–20%) of blackcurrant or chokeberry pressings. We assessed expansion rate, water absorption index (WAI) and water solubility index (WSI) of the produced extru-dates, the concentration of polyphenols, and antioxidant activity measured by FRAP method and ABTS method. The puffs with addition of chokeberry pressings had higher WSI values, higher phenolic acids, flavonols, and anthocyanins content, and higher antioxidant activity than puffcorn with addition of blackcurrant pressings. The corn puffs with addition of fruit pressings contained much higher concentrations of phenolic compounds and were characterized by much higher antioxidant activity than pure puffcorn. This confirms the usefulness of addition of such fruit processing by-products in order to manufacture functional food.