Physicochemical Properties Of Flour Research Articles

A study of the effect of the drying process on the composition and physicochemical properties of flours obtained from durian fruits of two ripening stages

Summary Durian cv. Monthong with two ripening stages (unripe and fully ripe) was subjected to microwave vacuumdrying (MWD) at 5.49 W g 1 and hot air drying (HAD) at 60 °C. With an increase in ripening degree, thestarch content was significantly (P ≤ 0.05) decreased from 40.08–40.42% to 9.44–11.76%. X-ray diffractionindicated that the crystalline pattern was changed from starch to sucrose. The starch granule morphologyof durian flour was conserved for both drying conditions. Peak gelatinisation temperatures of MWD andHAD flours were increased significantly (P ≤ 0.05) from 56.71–57.32 to 60.71–61.23 °C. Using differentdrying methods, MWD flour had less a*-value (P ≤ 0.05) than HAD flour. The peak viscosity and troughof the HAD unripe durian flour (5.92 RVU and 3.45 RVU, respectively) were significantly (P ≤ 0.05) lowerthan those of the MWD unripe durian flour (34.32 RVU and 11.57 RVU, respectively).Keywords Drying, durian, flour, hot air, microwave, ripening. Introduction Durian (Durio zibethinus Murr.) is one of the mostimportant fruit crops grown in Thailand, with anexport value of more than USD 175 million per year(Office of Agricultural Economics, 2011). The maingrowing areas are in eastern and southern Thailand.‘Monthong’ is one of the preferred cultivars amongconsumers, due to its sweet and buttery taste with asoft and fine texture. It is nutritionally rich in carbohy-drates, protein, fat, phosphorous, iron and vitamin A.In addition, it contains bioactive compounds with highantioxidant activity. Therefore, durian cv. Monthongis recommended as a nutritional supplement (around5–7%) to the normal diet (Poovarodom et al., 2010).To overcome the problem of oversupply during theharvest season and degradation of durian quality asfresh fruit, durian can be dried and kept as durianflour for use during the off season.Durian flour is normally made of unripe but fullymature fruit. Mature fruit had the highest starch con-tent at 3 days before ripening (Limpisathian et al.,2008). However, unripe fruit often has less taste andaroma than ripe fruit. During ripening, the composi-tion of the durian aril changes. Kalayanamitra et al.(2005) reported that the average dry matter, fat andtotal sugar contents of the unripe durian pulp wereincreased as the ripening stage progressed. However,the starch content was decreased. Variation in thechemical composition of the fruit may affect the func-tional properties of flour and thereby may affect itsutilisation as an ingredient in food formulas. Inbanana flour, as the ripening progressed, the moistureretention and water solubility index significantlyincreased, but the water absorption capacity decreased.This could be related to an increase in the sugar con-tent during the ripening stage (Gamlath, 2008).Knowledge of the functional and physicochemicalcharacteristics of flour is essential to determine its suit-ability for specific requirements in food such as snacks,bakery products and soup.Hot air drying (HAD) has been extensively used inmaking flour. However, during HAD, the physical,chemical, and sensory characteristics and the nutri-tional value in the food can be changed, resulting in areduction in the final product quality (Miranda et al.,2010). According to Ramesh Yadav et al. (2006), thepasting characteristics of HAD sweet potato starchwere decreased due to starch gelatinisation during

Physicochemical properties of flours and starches derived from traditional Indonesian tubers and roots.

Flours and starches isolated from traditional tubers and roots grown in Indonesia have physical and chemical properties suitable for certain food applications. Compared to other flour samples, cassava and canna flours contained the highest amount of total starch (TS) (77.4 and 77.1%, respectively). Taro starch had the lowest amount of TS among other starch samples with 75.4%. The highest amount of amylose was observed from yam and canna flours (25.2 and 23.2%, respectively). Among starch samples, canna starch contained the highest amylose content (30.4%), while taro had the lowest (7.6%). In terms of protein content, arrowroot flour had the highest amount (7.7%), in contrast to cassava flour which had the lowest (1.5%). Compared to other flours, canna and konjac flour were the most slowly digested which indicated by their high amount of resistant starch (RS). Canna starch had the highest swelling power and viscosity than other starches and flours. The clearest paste was observed from cassava flour and starch as opposed to konjac starch which was the most opaque paste.

In vitro protein digestibility and physico-chemical properties of flours and protein concentrates from two varieties of lentil (Lens culinaris)

The chemical composition of whole lentil flours and lentil protein concentrates prepared by alkaline extraction and iso-electric precipitation from Blaze and Laird varieties of lentil were studied. The protein composition of the flours and concentrates, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and size-exclusion high-performance liquid chromatography (SE-HPLC) showed that the extracted proteins were composed mainly of globulins and albumins. Trypsin inhibitor activity ranged between 0.94 and 1.94 trypsin inhibitor units (TIU) mg(-1) for the flours, but was markedly lower in the protein concentrates ranging between 0.17 and 0.66 TIU mg(-1). In vitro protein digestibility ranged between 75.90 and 77.05% for the flours, whereas significantly (P < 0.05) higher values, ~82.80 to 83.20%, were determined for the concentrates. Significant (P < 0.05) differences in colour (ΔE) were observed between the flours and the concentrates from both varieties. Thermal properties of both flours as studied by differential scanning calorimetry (DSC) were comparable. However, the endothermic parameters of the two protein concentrates were significantly (P < 0.05) different. Overall, the results show that in vitro protein digestibility of lentil protein concentrates is higher than that of the flours, however, both lentil flours and protein concentrates contain useful proteins that could serve as value-added ingredients in food formulations.

Influence of Allelic Variations of Glutenin and Puroindloine on Flour Composition, Dough Rheology and Quality of White Salted Noodles from Korean Wheat Cultivars

Allelic variations in glutenin and puroindolines of 26 Korean wheat cultivars were evaluated to determine their effects on the physicochemical properties of flour and quality of white salted noodles. Cultivars carrying Pina-D1b and Pinb-D1b exhibited a coarser particle size of wheat flour and a higher ash and damaged starch content than those with Pina-D1a and Pinb-D1a. Glu-B1b, Glu-D1f, Glu-B3d and Pina-D1a alleles exhibited lower protein content than other alleles. Glu-A1c, Glu-B1b, Glu-D1f Glu-B3d, Glu-B3i and Pinb-D1b alleles appeared to be related to a lower SDS-sedimentation volume than other alleles. In dough rheological properties, Glu-A1a and Glu-D1d alleles showed a longer mixing time on the mixograph and maximum dough height but Glu-A3e and Glu-B3i alleles had a lower mixing time on the mixograph and a lower maximum dough height than other alleles at Glu-1 and Glu-3 loci. Regarding the quality of white salt noodles, about 10% of the variations in the hardness of cooked noodles were explained by Glu-A1 and Glu-B3 loci. Hardness rankings of cooked noodles were Glu-A1a > Glu-A1c > Glu-A1c at the Glu-A1 locus. Glu-B3h showed higher cooked noodle hardness (5.10 N) than other alleles at the Glu-B3 locus (< 4.66 N).

Effect of carriers on physicochemical properties, antioxidant activities and biological components of spray-dried purple sweet potato flours

This work focuses on the impact of carriers on the physicochemical properties, antioxidant capacities and biological components of spray-dried purple sweet potato flours. The optimal carrier addition of maltodextrin (MD), β-cyclodextrin (β-CD) and their combination (MD/β-CD, 5/1) were 30, 10 and 24 g/100 g in terms of flour yield. Compared to the flour without carrier, flours with carriers had higher values in L*, fluidity, water solubility index, glass transition temperature, lower values in chroma, water absorption index and water holding capacity. The influence intensity of carriers on the physicochemical properties of flours followed the sequence of MD > MD/β-CD>β-CD. The flours with carriers were more dispersive and had smoother surface than flour without carrier. The addition of carrier had little effects on flours' sorption isotherm and the Halsey model presents the best goodness-of-fit to all flours. The flour with MD had higher retention rate of anthocyanins, flavonoids and total phenolics than flours without and with other carriers. The flour with MD has higher antioxidant activity (DPPH test) than flours with MD/β-CD or β-CD.

PREDICTION OF EXTENSOGRAPH PROPERTIES OF WHEAT‐FLOUR DOUGH: ARTIFICIAL NEURAL NETWORKS AND A GENETIC ALGORITHM APPROACH

ABSTRACTWheat‐flour dough is a viscoelastic material with nonlinear rheological behavior. Extensograph is a useful system for dough rheological measurement. Our purpose in this research was to apply soft computation tools for predicting the extensograph properties of dough from several physicochemical properties of flour. This study used the resulting model to suggest modifications of processing conditions for reducing economic loss and minimizing product quality deterioration. A generalized feed‐forward artificial neural network (ANN) with a back‐propagation learning algorithm was employed to estimate the extensograph properties of dough. Trial and error and genetic algorithm (GA) were applied in the training phase for developing an ANN with an optimized structure. Developed ANN using GA has excellent potential for predicting the extensograph properties of dough. Sensitivity analyses were conducted to explore the ability of inputs in predicting the extensograph properties of dough. Results showed gluten index was the most sensitive input in dough extensograph characterizations.PRACTICAL APPLICATIONSExtensograph is a suitable instrument for measuring the stretching properties of dough to make reliable statements about the baking behavior of the wheat‐flour dough in practical industrial applications and in research. Rheological measurements of each batch in the production line are very useful and make online and in‐time process adjustments possible, but this is usually impractical in an industrial setting. Therefore, accurate prediction of dough rheology could provide many benefits to the baking industry for satisfying consumer demands. In the current study, genetic algorithm‐neural network approach was applied to predict extensograph properties of dough as affected by physicochemical properties of flour. In comparison with trial and error, genetic algorithm can determine an artificial neural network's topology and inputs in less time with excellent performance in prediction. According to the results of sensitivity analyses, of the seven investigated inputs, changes in gluten index have the most effect on estimating extensograph properties of dough.

Effect of Fermentation on Physicochemical Properties and Oxalate Content of Cocoyam (Colocasia esculenta) Flour

The effect of fermentation on physicochemical properties and oxalate content of cocoyam (Colocasia esculenta) flour was evaluated. The cocoyam, white flesh was cleaned, washed, peeled, sliced into chips of 2–2.5 cm thickness, soaked in tap water and left to ferment for 24 h and 48 h. The fermented cocoyam was then drained, dried in cabinet dryer at 60∘C for 24 h and milled. The flour samples were passed through a 45 μm mesh size sieve. Unfermented cocoyam flour was also produced and served as a control. Calcium oxalate and some physicochemical properties of flours from the fermented cocoyam were compared with the unfermented flour. Results showed that fermentation effected a significant reduction in oxalate level (58 to 65%) depending on the fermentation period. The amylose content was higher in 48 h fermented flour (55.52%) than in 24 h (54.55%). Pasting (gelatinization) temperature decreased, and water absorption capacity increased markedly due to fermentation.

Physico-Chemical Properties of Flour, Starch, and Modified Starch of Two Rice Varieties

The physical and chemical properties of the flours, starches, and modified starches of indica rice and japonica rice were investigated in this paper. Results showed that the swelling powers of flour, starch, and phosphate starch [substitution degree (DS)=0.065] of japonica rice were significantly higher than those (DS=0.065) of indica rice. The transmittance of modified starches was highest; and that of flours was lowest. The pasting property investigated with rapid visco analyzer (RVA) indicated that the peak viscosity and breakdown value of paste with high swelling power were high. Furthermore, the effect of protein and amylose content on pasting property were investigated. The results of rheological properties determined using rheological rheometer showed that at the same temperature, the storage modulus (G') of flour, starch, and modified starch of indica rice was higher than that of japonica rice. For each variety, the G' of flour was the highest, while the G' of modified starch was the lowest.

Some physicochemical properties of flour from germinated sorghum grain

A Sudanese sorghum cultivar (Fetarita) was germinated for 3days. Stability and clarity of sorghum pastes, freeze-thaw stability, gel consistency, and swelling power were measured every 24h. There is no substantial difference in stability and clarity between flour samples from germinated and ungerminated sorghum, but a different behavior was observed between samples stored at room temperature and at 4°C. Cooked paste derived from germinated sorghum flour presented higher syneresis than that derived from ungerminated sorghum flour over the first three cycles but when the cycle number increased, both flours showed zero syneresis value. For the gel consistency the flours derived from germinated sorghum produced thinnest gels. The neutral and acid gel consistency increased when the germination time increased. Germination had not much effect on the swelling power of sorghum flour.

Rheological properties and bread making performance of commercial wholegrain oat flours

Three commercial wholegrain oat (WO) flours from Finland (WOF), Ireland (WOI) and Sweden (WOS) were evaluated for their bread making ability with the objective of finding predictive relationships between flour physicochemical properties and bread quality. Overall, significant differences were found in the bread making properties of the WO flours. Good bread quality was obtained when using WOS and WOI flour since breads showed high specific loaf volume and slice height as well as low density and hardness. Low quality breads were obtained when WOF flour was used. In addition, positive effects on oat bread quality were observed for low batter viscosity and high deformability, as obtained for WOS and WOI. Based on the physicochemical analysis of the flours, water hydration capacity was found to be the main reason for increased elasticity of WOF batters. Small flour particle size, damaged starch granules and high protein content were identified as the key factors causing increased water hydration capacity. These findings suggest that WO flours with coarse particle size, limited starch damage and low protein content result in superior oat bread quality.

Influence of puroindoline genotypes on grain characteristics, physico-chemical properties of flour and end-use quality of Korean wheats

Puroindoline genotypes, grain characteristics, physico-chemical properties of flour and end-use qualities of Korean wheat cultivars were evaluated to determine the influence of puroindolines genotypes and to provide on those characteristics. Nine Korean wheat cultivars carried Pina-D1a/Pinb-D1a, fourteen had Pina-D1a/Pinb-D1b, and three had Pina-D1b/Pinb-D1a. Pina-D1b/Pinb-D1a and Pina-D1a/Pinb-D1b genotypes showed significantly higher 1000-kernel weight and hardness index in grain characteristics, higher flour yield, average particle size, ash and protein content, SDS-sedimentation volume, water absorption and mixing time of mixograph, thickness of noodle dough sheet and lower values in lightness of flour and cookie diameter than Pina-D1a/Pinb-D1a genotype. The Pina-D1b/Pinb-D1a genotype showed significantly higher damaged starch content and water retention capacity than other genotypes. Hardness index of grain was positively correlated with flour yield and average particle size of flour. Those parameters were positively correlated with damaged starch, water retention capacity, SDS-sedimentation volume and water absorption of mixograph, and negatively correlated with lightness of wheat flour. In end-use qualities, thickness and lightness of noodle dough sheet and cookie diameter were correlated with hardness index, milling performances and physical properties. However, bread volume and texture of cooked noodles were not influenced by milling performances and physical properties.

Effect of gamma‐ray irradiation on the physicochemical properties of flour and starch granule structure for wheat

SummaryEffect of gamma irradiation on the physicochemical properties of flour and starch granule structure of wheat was compared to non‐irradiated wheat. The moisture content of wet gluten and titratable acidity of wheat flour were significantly affected by gamma irradiation. This treatment also destroyed the starch granules of wheat grain and their breakage augmented as the dose of gamma irradiation increased, apparently resulting in the increase of small starch granules. Probably, these results were due to the disruption of large molecule, such as proteins, lipids and starch. The irradiated wheat flour for RVA pasting properties (flour viscosity) was also evaluated. Besides the difference in RVA profile, starch pasting curves showed a considerable decrease for six main parameters as gamma irradiation dose at different velocity increased.

Production of Bambara Groundnut (Voandzeia subterranean) Flour for Use in the Preparation of Koki (a Steamed Cooked Paste): Effect of pH and Salt Concentration on the Physicochemical Properties of Flour

The present study is part of a project aimed at producing bambara groundnut (Voandzeia subterranean) flours for the preparation of koki (a steamed cooked paste). The flours were produced from the black (BBG) and white (WBG) varieties by the combined processes of soaking, drying, dehulling and milling. Some physicochemical characteristics of the flours were evaluated and the effects of flour particle size, salt concentration and pH on their functional properties were investigated. Significant varietal influence was indicated on the proteins and carbohydrates with the WBG variety showing high level of proteins (19.7%) and the BBP variety the highest carbohydrate content (61.7%). It was equally observed that an increase in NaCl tends to induce a reduction in the water absorption capacity (WAC), foam capacity and emulsion properties. The emulsion and foam capacities were observed to be at their minimum values within the pH range 2 and 4.

Selected Physicochemical Properties of Flour from the Root of African Fan Palm (Borassus aethiopum)

Chemical composition of African fan palm (Borassus aethiopum) root and some physicochemical properties of the flour obtained from the root were investigated. It was found that the root was relatively high, on dry weight basis, in protein content (13.41%), starch (65.12%), crude fibre (7.72%), and total phenolics (1.94%). The processing characteristics of the root showed that the flour fraction obtainable from it ranged from 14.7–16.3% (on whole root basis) while the energy value of the flour (17.23 KJ/g) was relatively high. The elemental composition of Borassus aethiopum root revealed that it was high in potassium (812.21 ppm) and phosphorus (736.33 ppm), while it was low in iron (8.23 ppm) and manganese (4.41 ppm). Elements such as copper, zinc, aluminum, and silicon were not detected. The functional properties of the root flour showed that it had relatively high water absorption capacity (241.24%), moderate oil absorption capacity (192.42%), moderate bulk density (1.22g/cm3), and foaming capacity (2.31%). The maximum solubility and swelling power of the root flour were 15.7 and 18.9%, respectively, at the highest temperature of 95°C. The pasting characteristics of the flour revealed that the peak viscosities at different concentrations were 260 B.U. (5%), 340 B.U. (8%), and 520 B.U. (10%), and these peak viscosities were attained after reaching 95°C. Other pasting characteristics of flour from Borassus aethiopum root revealed that the flour could be used in such composite applications as those flours from other crops (i.e., maize, cocoyam, water yam, and plantain).

Analysis of genotypic diversity in starch thermal and retrogradation properties in nonwaxy rice

A total of 236 nonwaxy rice including 56 landraces (landrace set) obtained from the germplasm center and 180 cultivars and breeding lines (breeding line set) obtained from various breeding programs were studied for the genetic diversity of flour thermal and retrogradation properties, focusing on comparison of the differences between the landrace set and breeding line set. Wide diversity was found in all flour physicochemical properties, e.g. peak temperature ( T p) ranged from 63.2 to 79.8 °C, width at half peak height (Δ T 1/2) of gelatinization ranged from 4.7 to 10.5 °C; enthalpy of gelatinization (Δ H g) ranged from 5.6 to 11.4 J/g, and retrogradation percentage ( R%) ranged from 0.2% to 54.2%. The breeding line set had a larger range of thermal properties and R% than in the landrace set, whereas the range of retrogradation enthalpy was similar between two sets. The mean for all parameters differed between the two sets; mean Δ T 1/2 of the landrace set was smaller than in the breeding line set, whereas other parameters were larger in the landrace set than the breeding line set. Correlation analysis showed that apparent amylose content was positively correlated with Δ H g ( r = 0.65, P < 0.001) and R% ( r = 0.68, P < 0.001), and negatively correlated with Δ T 1/2 ( r = −0.28, P < 0.001). All thermal and retrogradation properties themselves were correlated; the correlation between Δ T 1/2 and all other parameters was negative, whereas all other pairs were positive.

Physicochemical Properties of Sweet Potato Flour and Starch as Affected by Blanching and Processing

AbstractThe effects of blanching on physicochemical properties of flours and starches prepared from two varieties of sweet potatoes (Mun‐Kai and Negro) were studied and compared. The pasting temperature and peak viscosity of starches, respectively, were 74 and 80 °C and 381 and 433 RVU. The pasting temperature (74.0‐94.8 °C) of flours was greater than that of starch, depending on the variety and blanching process. However, the peak viscosity (ca. 103‐120 RVU) of flours was lower than that of the corresponding starches. Partial gelatinization of starch granules was observed as a result of a 1‐min blanching. Composition of starch and flour was found to affect swelling power and solubility. The starch content of starches, flours from unblanched sweet potato and flours from 1‐min blanched sweet potatoes were 97; 66.3 and 74.9; as well as 36.6 and 40.4%, respectively. Amylose content of flours and starches varied from 17.2‐20.8%.

Effect of Raw Material Preparation on Rice Vermicelli Quality

The physicochemical properties of high amylose rice flour prepared from wet milling and dry milling were examined and the rice vermicelli quality made from these flour samples was evaluated. The effect of flour particle size on rice vermicelli quality was also determined. The milling method affected chemical compositions and all physicochemical properties of the flour. A higher degree of starch damage occurred in drymilled flour. Rice vermicelli made from dry-milled flour had higher cooking losses and softer texture than that made from wet-milled flour and the commercial reference products. Flour particle size influenced both cooking and textural quality of rice vermicelli but did not influence the water absorption index. Flours with larger particle sizes gave vermicelli with higher cooking loss and less desirable texture than flours with smaller particle sizes. Flour with particle sizes less than 200 mesh produced acceptable vermicelli in terms of cooking and textural quality.

Physicochemical Properties of Flours that Relate to Sorghum Couscous Quality

ABSTRACTFlours from eight sorghum cultivars were evaluated for their couscous‐making ability with the objective of finding predictive relationships between flour physicochemical properties and couscous quality. Chemical composition, physical characteristics, and pasting and gelatinization properties of the flours were determined. A laboratory procedure was used to prepare couscous. Couscous properties were evaluated and compared to a laboratory‐prepared and a commercial durum wheat couscous. Hard grain produced flours containing a high proportion of coarse particles with low ash and high damaged starch content and yielded a higher proportion of desirable sorghum couscous granules. A variety of colors ranging from brown to yellow were obtained when flours were processed into couscous. Cooked sorghum couscous stickiness was positively correlated (r = 0.89, P &lt; 0.01) with the amount of damaged starch in flour. Cooked couscous hardness correlated positively (r = 0.79, P &lt; 0.05) with apparent amylose content of flour and correlated negatively (r = ‐0.75, P &lt; 0.05) with flour peak viscosity. Durum wheat couscous was lighter and had more yellow color than sorghum couscous. Sorghum couscous was stickier and harder than durum wheat couscous. Addition of 2% oil to the cooking water considerably improved the texture of some sorghum couscous to a level comparable to that of durum wheat couscous.

Calcium oxalate and physico-chemical properties of cocoyam ( Colocasia esculenta and Xanthosoma sagittifolium) tuber flours as affected by processing

Calcium oxalate and some physico-chemical properties of flours from three cultivars of Colocasia spp. (coco-india, ede-ofe and inimbu) and one Xanthosoma sp. (ede-uhie) — steeped (30 °C), boiled (90 °C) and roasted (165 °C) — were compared with those of untreated flours. Results showed that boiling effected the highest oxalate reduction, especially in inimbu. The highest rate of change of oxalate reduction was also observed in inimbu for up to 30 min of boiling. Edeofe superceded it afterwards, even up to the 60th minute of processing. Gelatinization temperature decreased, and water and oil absorption capacities increased markedly due to the three processes. Boiling and roasting effected reduction in cold-paste viscosity, while an inconsistent trend resulted from steeping. Statistical analysis using an analysis of variance (ANOVA) technique ( P < 0.01) showed that the effects of cultivar and process time were significant on the calcium oxalate due to steeping and boiling. Process time variation in steeping and boiling of inimbu on both water and oil absorption was significant. On the other hand, only the effect of cultivar on viscosity of both steeped and boiled samples was significant.

The effect of ball-milling on phospholipid extractability and the breadmaking quality of flour

This paper describes the effect that ball-milling for various periods has on the mechanical dough development (MDD) breadmaking and physicochemical properties of flour. The quantity of water-saturated butanol-soluble phospholipid extractable from the flour at room temperature is negatively correlated with changes in loaf volume and positively correlated with MDD work input. However, this is an artefact of the starch damage caused by ball-milling. That is, phospholipid is acting as a marker for another variable and giving the false impression that a functional relationship may exist. Although there is an increase in protein solubility, wheat proteins analysed by reversed-phase high performance liquid chromatography (RP-HPLC) and polyacrylamide gel electrophoresis in the presence of sodium dodecyl-sulphate (SDS-PAGE) do not appear to be functionally altered by ball-milling.