Impact of hydroxypropylation coupled with extrusion treatment on the morphological, structural, and rheological properties of sorghum and corn starch.

The purpose of the present study to prepare hydroxypropyl derivatives (HP) instant (partially cold-water swell-able) starches via extrusion technique (Ex) from sorghum and corn. The native and hydroxypropylated (at propylene level 5 % and 12 %) starch extrudates were evaluated for functional, structural, thermal and rheological properties. The development of extrudates provides ease to industries as they are easily soluble in aqueous mediums and does not require any prior heating. The degree of substitution (DS) for all extrudates varied between 0.0083 and 0.1530 which is under limit and save to consume. The X-ray diffraction (XRD) analysis revealed that all extrudates exhibited V-type pattern while the intensity of peaks increased due to hydroxypropylation. The starch extrudates showed gel-like behavior since storage modulus (G') was greater than loss modulus (G″). Non-Newtonian shear thinning behavior was observed for all extrudates. At lower temperature, HP-Ex at higher substitution level (12 %) demonstrated higher complex viscosity than native and low-substituted extrudates. Creep recovery of HP-Ex dispersion was more pronounced than native extrudates suggesting elastic nature of sorghum and corn starch extrudates. The differential scanning calorimetry (DSC) results revealed that HP-Ex were observed to gelatinize at lower temperatures and needed lower enthalpy of gelatinization (ΔHgel) because of their weakened structure after modification.

Enhancing functional properties of rice starches through hydroxypropylation for development of reduced-fat white sauces.

Present study investigated the preparation of commonly used white sauce with 50 % less added fat by using 10 % hydroypropylated Irri and Basmati rice starches in the formulation. The sauces incorporated with hydroxypropylated starches exhibited significantly lower gelatinization temperature and time, while the change in maximum viscosity was insignificant. Significantly improved stability at ambient, refrigeration, and freezing temperatures of reduced-fat white sauces was observed whereas change in the taste was insignificant. Basmati hydroxypropylated starch containing white sauce significantly mimicked the sensory properties of full-fat sauces. The hydroxypropyl groups were found to be 1.06 % and 1.16 % for Basmati and Irri hydroxypropylated starches, respectively. These values fall below the specified limit set by the Food and Drug Administration for the food grade hydroxypropylated starches. Significant improvements in peak viscosity, swelling power, solubility, percent transmittance, and water retention capacity were observed after the chemical modification of both rice varieties.

A combined use of different functional additives for improvement of wheat flour quality for bread making.

BACKGROUND: Low-protein wheat flour can produce bread with poor texture and appearance, reducing its nutritional value and market appeal. This is a growing concern for both the food industry and consumers relying on wheat as a dietary staple. The present study evaluated the individual and combined effects of bacterial xylanase (BX), maltogenic α-amylase (MG), vital gluten (VG) and ascorbic acid (AA) with respect to improving weak flour properties for bread making. RESULTS: BX, VG and AA improved gluten Index (GI), whereas MG was employed for optimizing amylolytic-activity in flour. VG increased the water absorption (WA) capacity of flour and prolonged dough development time (DDT). The dough stability (DST) was increased by BX and VG. BX and MG decreased crumb firmness (CF) and showed anti-staling effect. All additives reduced bake loss, increased loaf volume (LV) and retained or improved sensory attributes of bread. However, MG at 60 mg kg-1 (MG60), BX at 30 mg kg-1 (BX30), VG at 5% (VG5) and AA at 50 mg kg-1 (AA50) were found to be the most suitable for evaluating in combinations. Ternary combinations of MG60, BX30, VG5 or AA50 imparted significantly (P < 0.05) positive impacts on GI, WA, DDT, DST, CF, LV and sensory attributes compared to control, individual and binary combinations. CONCLUSION: The PCA suggested that a combination of MG60 + VG5 was more similar to MG60 + BX30 + VG5, whereas, MG60 + BX30 and MG60 + AA50 were more related to MG60 + BX30 + AA50 combination, but all of these combinations showed the improvement in the characteristics compared to control flour. © 2023 Society of Chemical Industry.

X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and Ravaz index.

Annual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning (1995 to 1999) and end (2017 to 2020) of the lifetime of a vineyard initially planted in 1991 and removed in 2021. X-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits. Modeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay of later rings, consistently shortening ring width throughout the lifetime of the vine. Ravaz index, juice pH, photosynthetic assimilation and transpiration rates, and instantaneous water use efficiency are correlated with scion trunk radius. Ultimately, our research indicates that rootstocks modulate secondary growth over years, altering physiology and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species.

Comparative study on morphological, rheological and functional characteristics of extruded rice starch citrates and lactates.

Two levels of chemically modified starches (starch citrates and lactates) prepared at 20% and 40% w/v concentration was subjected to extrusion to produce pregelatinized starches (PG). Starch citrates and lactates modified at 20% and 40% level were referred as (SC20 and SC40) and (SL20 and SL40), respectively. These PG starches underwent significant structural changes during extrusion as depicted by scanning electron micrographs. Native starches showed lower swelling power and water binding capacity but formed harder gels compared to chemically modified pregels. The dynamic rheology of these polymers (extruded modified starches) suggested visco-elastic property i.e. (G' > G''). Citrates demonstrated higher G' than lactates in both frequency and temperature sweep tests. Stability of storage moduli over entire temperature range confirmed that addition of citrates and lactates led to strengthening of gel structure through cross linking and esterification. Non-newtonian behavior was shown by all samples as determined through steady shear flow test with flow behavior index <1. Starch citrate (SC20-PG) demonstrated higher shear stress values. While, SC40-PG depicted anti-thixotropic behavior as measured through in-shear structural recovery measurements. On the basis of results obtained, the dual modification (chemical followed by extrusion) may impart fruitful applications in various food products.

Combined effects of hydroxypropylation and alcoholic alkaline treatment on structural, functional and rheological characteristics of sorghum and corn starches.

This study describes the effects of hydroxypropylation (HP) on sorghum and corn cold water soluble (CWS) starches prepared via alcoholic alkaline treatment (AAT). Propylene oxide (5% and 12% on starch weight basis) was used to modify both sorghum and corn starches. SEM analysis revealed that HP modification prior to AAT altered the granular morphology of native CWS starches. The characteristic peaks at 2980.28 cm-1 and 2979.87 cm-1 indicated the presence of hydroxypropyl groups and the complete loss of the granular order for HS12-CWS (hydroxypropylated sorghum CWS starch treated with 12% propylene oxide based on dry starch weight) and HC12-CWS (hydroxypropylated corn CWS starch treated with 12% propylene oxide based on dry starch weight) starches. Increase in swelling power and water binding capacity of HP modified CWS starches was observed. However, Percent transmittance was significantly reduced due to fragmented water-soluble granules. HP-modified CWS starch gels exhibited a more rigid gel network. Broader linear viscoelastic range suggesting greater stability and well dispersed behavior of HP-CWS starches. High G' values of HP-CWS starches were due to the ordered and elastic gel network that resisted deformation. Furthermore, all HP-CWS starches exhibited higher shear and thermal resistance compared to unmodified CWS starches.

Structural, functional and digestibility characteristics of sorghum and corn starch extrudates (RS3) as affected by cold storage time.

The aim of the study was to compare the properties of resistant starch (RS3) formed during extrusion of corn and sorghum starches. The extrudates were stored for 7 and 14 days at 4 °C to allow for molecular rearrangement i.e. retrogradation. The extruded starches were analyzed for enzymatic digestibility, long range (X-ray diffraction, XRD) and short range (FTIR) molecular order, thermal characteristics (DSC) and rheological properties as affected by temperature. The highest RS (70.64%) was obtained for sorghum extrudate (ES14) as compared to corn extrudate (EC14) (64.90%), on 14th day of storage. The increase in RS correlates with the increase in percent crystallinity (%Xc), too. The (ES14) reported the highest %Xc among all extrudates i.e.37.83. The XRD results showed an additional peak at 13° and 20°, reflecting the formation of V-type pattern in all samples. The FTIR spectroscopy also exhibited increase in the ratio of 1047 cm-1/1151 cm-1 and 1047 cm-1/1022 cm-1. The extruded starch showed significantly higher thermal stability and lower cold paste viscosity. The significant (p ≤ 0.05) decrease in the glycemic index was obtained as the storage time increased. The (ES14) exhibited glycemic index equal to (EC14) i.e.55.53 and 52.53, respectively; thereby making it a suitable substitute of corn starch.

Effects of cross linking and/or acetylation on sorghum starch and film characteristics.

In the present study, starch was modified by a) cross-linking through addition of 3% mixture of sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) based on starch weight b) acetylation through addition of 2%, 4% and 6% acetic anhydride based on starch weight c) dual modification i.e. cross-linking using 3% mixture of STMP and STPP followed by acetylation at 2%, 4% and 6% levels based on starch weight. These starches were then used to develop edible films followed by their characterization. Experimental results revealed that films with increased thickness were obtained from acetylated and cross linked starches whereas, dual modified starch films had reduced thickness compared to native starch film. Films from acetylated and dual modified starches retained more moisture compared to native and cross linked starch films while dual modified starches were more water soluble than acetylated and native starch films. All modified starch films were more clear and transparent compared to native starch films. Films from acetylated starches depicted lower tensile strength but they were more elastic and flexible than native and cross linked starch films. In contrast, dual modified starch films showed excellent mechanical properties and lower water permeability compared to native starch film.

Comparative study on citric acid modified instant starches (alcoholic alkaline treated) isolated from white sorghum and corn grains.

This study investigated the impact of citric acid modification combined with alcoholic-alkaline treatment on physicochemical, textural and rheological properties of sorghum and corn starches. Both starches were modified with citric acid (CA) using concentrations (20 and 40%) w/w and were named as SCA and CCA, respectively. SEM analysis revealed that CA modified CWS (cold water-soluble) starches had cracks and more sharp edges as compared to their native counterparts. In FTIR spectra a new peak at 1730.50 cm-1 and 1733.12 cm-1 confirmed formation of distarch esters for SCA40 and CCA40. Increase in swelling power of CWS starches was observed after citric acid modification. Textural analysis showed that SCA20 and SCA40 formed smooth and soft gels suggesting reduced retrogradation tendency of these starches. The broader linear viscoelastic region of CCA40 and SCA40 indicated high shear resistance and well dispersed behavior of CWS citrates. Moreover, it was observed that all CWS starches showed increase in storage modulus (G') and loss modulus (G″) values at higher frequencies indicating elastic behavior. CA modification conferred heat and shear stability to starches. This study provides the basic knowledge for the application of CA modified CWS starches in many instant, refrigerated and frozen food products.

Characterization of hydroxypropylated-distarch phosphate barley starch and its impact on rheological and sensory properties of soup.

Barley starch was dual modified by hydroxypropylation using 8% and 12% propylene oxide, separately, based on starch weight (dry basis) followed by cross-linking through addition of 1% mixture of sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) to form 8HPCL and 12HPCL E1442 (hydroxypropylated-distarch phosphate) barley starches, respectively. These modified starches were incorporated at 5% and 8% levels in soups. Functional characteristics of starches like swelling power, solubility and water retention capacity greatly improved after dual modifications. Paste clarity increased fivefold in case of 12HPCL (starch prepared using 12% propylene oxide and 1% mixture of STMP and STPP) modified barley starch. Higher level of hydroxypropylation also declined the retrogradation process in starches. All soups demonstrated thixotropic behaviour with flow behaviour indices less than one. Soup [S-(8HPCL)8] made with addition of 8% (8HPCL) barley starch demonstrated highest linear viscoelastic region (LVR), yield stress (τy) and complex viscosity (Ƞ⁎). Lowest value of tan δ (0.09) was also observed for S-(8HPCL)8 soup, suggesting its higher consistency. Native barley starch when added to soup at a level of 5% was the least acceptable in terms of sensory characteristics.

Comparative study on effects of citric and lactic acid treatment on morphological, functional, resistant starch fraction and glycemic index of corn and sorghum starches.

The present study isolated starch from corn and sorghum grains through wet milling procedure. Sorghum starch is considered an alternative to corn starch in future, due to similar functional properties. However, agronomically sorghum is a cheap input cost crop compared to sorghum and can grow in drought hit areas. Lactic acid and citric acid modifications along with heat-moisture treatments were performed on both sorghum and corn grains followed by their comparison in terms of functional, textural, thermal, pasting and digestibility characteristics. For both corn and sorghum starches, the resistant starch increased after chemical modifications. The RS content of acid and acid-heat moisture treated starches were in the range of 77.9-90%, significantly higher than those of native starches (64.6-68.8%). The modifications increased the gelatinization temperature, decreased the peak and cold paste viscosity of starches. Chewiness significantly reduced after lactic and citric acid treatment along with heat-moisture treatments. The crystallinity to amorphous ratio measured through Fourier Transform infrared reduced after all chemical treatments. Percent light transmittance was further reduced after heat-moisture treatments, however the effect on corn starch was more pronounced i.e. it declined from 16.5 to 5.2%. The acid-heat moisture treatments had considerably lowered the glycemic index of starch. The GI reduced from 74 to 49.7 and 60 to 48.5 when treated with acid in the presence of heat and moisture. Thus, these starches could be used in production of low-calorie foods.

Rice starch citrates and lactates: A comparative study on hot water and cold water swelling starches.

In the present study, modifications were done by varying concentration of citric and lactic acid (20 g and 40 g) to produce starch citrates (SC20, SC40) and lactates (LA20, LA40), followed by alcoholic alkaline treatment to produce cold water swelling modified starches (CWS). These modified starches were then compared to their native hot water swelling (HWS) counterparts in terms of functional properties. The CWS starches demonstrated instant viscosity even at room temperature and thus eliminate the need of heating assembly. The CWS (SC40) showed the highest swelling power and water binding capacity among all samples. Morphological characteristics revealed enlargement and roughening of granules after alcoholic alkaline treatment. Absence of 1047 cm-1 peak in FTIR spectra of CWS samples verified the loss of crystalline structure. The least percent retrogradation of 31.33% was exhibited by HWS SC40. Percent increase in hardness of gels after 7 days' storage showed remarkable decline in retrogradation tendency of CWS samples. Absence of gelatinization peak and high initial viscosity of CWS samples confirmed gelatinization due to alcoholic alkaline treatment.

Physical, thermal, mechanical and barrier properties of pearl millet starch films as affected by levels of acetylation and hydroxypropylation.

Starch-based films possess potential application in food packaging, due to their biodegradability, lower cost, stretchability and clarity. The aim of this work was to develop novel edible films from native, acetylated and hydroxypropylated pearl millet starches with improved flexibility, transparency and water barrier properties. Each film contained a fixed concentration of starch (3 g/100 g) and glycerol (30%, w/w based on starch weight). The effect of levels of acetylation (4% and 8%, w/w) and hydroxypropylation (10% and 30%, w/v) on the rheological, physical, thermal, mechanical and barrier properties of films was investigated. SEM results showed that modified starch films possessed smoother surface in comparison to native starch film (NF). Rheological evaluation depicted that filmogenic solution of 30% hydroxypropylated starch was more viscous than other solutions. Films containing 4% and 8% acetylated starches showed excellent moisture barrier property as depicted by their low water vapor permeability (WVP) and water solubility (WS). The extent of these improvements depended on the levels of acetylation. Elongation at break (%EAB) and transparency (%T) of 10% and 30% hydroxypropylated starch films were higher than NF and increased with increasing amount of propylene oxide. Glass transition temperature (Tg) was lowered by addition of modified starches in film formulation.

Rheological characterization of cold water soluble rice (Oryza sativa) starch lactates and citrates prepared via alcoholic-alkaline method.

The present study prepared citrates and lactates from rice starch which were then given alcoholic-alkaline treatment to produce cold water soluble (CWS) starches. These chemically modified starches were then compared in terms of rheological parameters to their hot water soluble starches (without alcoholic-alkaline treatment). FTIR spectra showed characteristic peak between 1710-1727 cm-1 which confirmed esterification of starch via citrate and lactate groups. All samples demonstrated viscoelastic character i.e. storage moduli (G') exceeded loss moduli (G″). Both CWS and HWS starch citrates prepared by addition of 40 g citric acid to 100 g of starch exhibited highest G' and G″ suggesting highly structured and strong gels. Dynamic frequency and temperature sweep clearly showed that alcoholic alkaline treatment disrupted the granular conformity due to gelatinization of starch and as a result CWS starches were more susceptible to break down. Steady shear flow test confirmed that all samples were non-Newtonian while results of In-shear structural recovery measurements indicated anti-thixotropic behavior of CWS starch lactates.

Time-Kill Kinetics of Lipid Fractions Isolated from Condiments against Foodborne Pathogens.

Lipid fractions that are extracted from condiments have a wide array of biological potential and are commonly utilized for medicinal and culinary applications. This investigation aims at determining the antimicrobial potential of lipid fractions isolated using two different solvent systems against five foodborne pathogens. The antibacterial efficacy was tested after 0, 1, 2, 3 and 24 h of incubation with the active agent. The leakage of cellular content was assessed at 1 and 2 h of incubation. Scanning electron microscope (SEM) images were obtained after 18 h of contact time with lipid fractions at their minimum inhibitory concentration (MIC). From the results obtained from time-kill and cell constituents release tests, it could be concluded that during 3 and 1 h of incubation, the lipid fractions were more potent against Gram-negative isolates (Escherichia coli ATCC 8739). However, prolonged incubation with the active agent inhibited Gram-positive isolate, i.e. Listeria monocytogenes ATCC 13932. SEM images of treated microorganisms also confirmed the inhibitory action of selected lipid fractions against all the tested pathogens. The cellular morphology of the bacteria was completely altered after 18 h of incubation with the lipid fractions. The results of the present study corroborate significant inhibitory effects and disruption in bacterial cell integrity following prolonged incubation with these lipid fractions. The results also affirm the use of the tested lipid fractions in food systems.

Native and modified Sorghum starches as wall materials in microencapsulation of nutmeg oleoresin.

The effect of the partial or total substitution of gum arabic (GA) with native (NA), octenyl succinic anhydride (OSA) and succinylated (SUC) sorghum starches on microencapsulation of nutmeg oleoresin was studied using spray drying technique. The oleoresin with 10% load is emulsified by using three different combinations of GA along with native and modified sorghum starches. The proportion of GA and sorghum starch was fixed at 75:25, 50:50, and 25:75. Most of the feed emulsions were having good emulsion stability and lower emulsion viscosity. The highest oil retention of 95% with 84.07% encapsulation efficiency was achieved when GA: NA starch was used in the fraction of 25:75. The highest encapsulation efficiency of 95.38% was obtained by GA: OSA in a ratio of 75:25. Results obtained suggested that both NA and OSA starches could be considered as a good alternative to gum arabic for microencapsulation.

Effect of guar gum coatings containing essential oils on shelf life and nutritional quality of green-unripe mangoes during low temperature storage.

This study investigated the effect of treatment of guar gum coating coupled with essential oils. Harvested unripe green mangoes (UGM) were preserved using edible coatings containing essential oils of Nigella sativa, Coriandrum sativum, Foeniculum vulgare and Laurus nobilis derived using two different solvents (methanol and ethanol) and stored at refrigeration temperature (10°C, 80-85% relative humidity). Physiological and biochemical parameters that assess the quality of fruits were determined. Microbiological analysis was also performed at the start and end of shelf life. Generally, it was observed that ethanolic essential oils supplemented coatings conferred a greater retention of fruit quality as compared to both controls. Bacterial counts were significantly reduced in fruits that were coated with ethanolic essential oil edible coatings. Secondly, the coatings supplemented with ethanolic and methanolic essential oils extended shelf life up to 24days whereas treated and untreated control decayed after 10 and 6days respectively (P<0.05). These results suggested the application of these edible coatings for preservation of unripe green mangoes during cold storage.

Comparison Of Dietary Practices And Body Mass Index Among Educated Housewives And Working Women In Karachi.

BACKGROUND: Body Mass Index (BMI) is considered as a major determinant of health. The objective of study was to find out differences between dietary practices, as well as BMI in educated housewives and working woman. It is supposed that both study groups may have difference in work pressures with resultant diverse preferences for food. This can affect health status particularly in relation to obesity in women. Furthermore, we selected participants with 14 years' education expecting basic awareness of healthful diet. METHODS: This cross-sectional study had a convenient sampling method and sample size of 600 with 300 house wives and 300 working women, aged 35-45 years. Dietary habits were recorded by interview. Body Mass Index was calculated by standard formula, and results obtained by Chi-Square using SPSS-17. RESULTS: Working women had healthier dietary practices. Number of meals, fruits, fish/ poultry and water consumption was better in working mothers with significant p-value <0.00.1. Intake of vegetables and fast food was found similar. BMI comparison showed that majority of housewives were noted as overweight whereas working women showed normal weight (p-value <0.001). Most housewives responded that they have a sedentary life style as opposed to working women p-value <0.001. Self- assessment of diet quality was comparable as it was mentioned moderate by most of the participants, however more working females accepted that they need to improve their diet and would need expert advice. CONCLUSIONS: Healthier BMI, active life style and better dietary habits were witnessed in working women as compared to housewives.

Characterization and utilization of hydroxypropylated rice starches for improving textural and storage properties of rice puddings.

This work investigated the effect of hydroxypropylation on the physicochemical characteristics of Basmati and Irri rice starches with milk and water. The effect of hydroxypropylated starches on the storage, texture stability and sensory characteristics of rice pudding was studied. Pudding was prepared by replacing 3%, 5% and 10% of Irri rice flour with native and hydroxypropylated starches isolated from two predominant rice varieties of Pakistan; Irri and Basmati. Syneresis was not observed in pudding made with hydroxypropylated starches and native basmati starch. On the contrary, pudding prepared with Irri rice flour and Irri starches showed poor keeping quality. Sensory analysis showed that modification of rice starches did not significantly alter the color, flavor, taste and overall acceptability of pudding. The results suggested that rice pudding, a very popular dessert of South Asia could be prepared with improved storage characteristics using hydroxypropylated starches without altering the taste and acceptability of the product.

Utilization of chemically modified pearl millet starches in preparation of custards with improved cold storage stability.

Custards were prepared using five ingredients: milk powder, modified pearl millet starch, sugar, vanilla essence and water. The effect of adding hydroxypropylated starch (HPS), succinylated starch (SUS), oxidised starch (OXS) and acetylated starch (ACS) on cold storage stability, pasting, textural and sensory properties was studied and compared to custards containing native pearl millet starch (NS). Interestingly, all chemically modified starches reduced syneresis and no water weeping was observed in custard sample incorporating hydroxypropylated starch (HPC) even after 7days of cold storage. Viscoamylographic analysis revealed that custard containing succinylated starch (SUC) had the highest peak viscosity (108.8 BU), whereas HPC showed the least set back viscosity (19.0 BU). Sensory results suggested that assessors preferred HPC over other custards. Custards are preferred for their chewy semi-solid texture. Incorporation of hydroxypropylated starch (HPS) increased hardness, gumminess and chewiness which subsequently led to higher sensory scores during subjective analysis. Also, no retrogradation peak was observed for HPS and acetylated starch (ACS) when rescanned after 14 days. Thus, it could be concluded that HPS could be used in custards to confer low temperature stability by reducing syneresis.