RESUMO
OBJECTIVE: To compare the occurrence and to determine relationship of dietary practices with hypertension between housewives and working women.. METHODS: The cross-sectional study was conducted at Karachi University and Dow University of Health Sciences, Karachi, from January to April 2015, and comprised working women and housewives who were enrolled using convenient sampling. Data was collected on consumption of fruits, vegetables, poultry/fish and fast food. Blood pressure and body mass index were noted and interpreted according to World Health Organisation classification for Asian population. Normal reference range of blood pressure was taken as Systolic100-120mmHg, Diastolic 60-90 mmHg, and mean value as 120/80mmHg. Data analysis was done using SPSS17. RESULTS: There were 600 subjects; with 300(50%) housewives and as many working women. Mean age of housewives was 35.56}7.53 years, and that of employed women 35.44}6.65 years. Among the housewives, 96(32%) had normal blood pressure while the corresponding number in the other group was 198(66%) (p<0.001). In terms of relationship body mass index with hypertension, out of the 204(68%) hypertensive housewives, 90(44.1%) were overweight, and of the 102 hypertensive working women, 40(39.23%) had normal weight range. Most housewives reported a sedentary lifestyle as opposed to working women (p<0.001).. CONCLUSIONS: Being a housewife was in itself found to be a contributing factor in hypertensive disorders.
Assuntos
Pressão Sanguínea/fisiologia , Dieta/estatística & dados numéricos , Mulheres Trabalhadoras/estatística & dados numéricos , Estudos Transversais , Feminino , Humanos , Hipertensão/epidemiologia , Paquistão/epidemiologiaRESUMO
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.
RESUMO
OBJECTIVE: To compare levels of depression and locate difference in effects of dietary practices on depression severity in housewives and working women. METHODS: This comparative, cross-sectional study was conducted at the University of Karachi and the Dow University of Health Sciences, Karachi, from January to April 2015. Convenient sampling method was used. Participants included educated women, comprising housewives and working women aged 35-45 years. A structured questionnaire was used to collect data about participants' dietary habits. Depression levels were recorded through Patient Health Questionnaire-9 questionnaire. SPSS 21 was used for data analysis. RESULTS: Of the 600 participants, 300(50%) were housewives and 300(50%) were working women. The mean age of housewives was 35.56±7.53 years and that of working women was 35.44±6.65 years (p=0.827). Study outcomes revealed that dietary habits influenced severity of depression. In none/minimal category, most women in both study groups were those who were taking 3 meals [18(14.5%) housewives and 114(52.8%) working women], 8 or more glasses of water [16(16%) housewives and 94(48%) working women]and fast food rarely[20(12%) housewives and76(44.7%) working women]. A high number of women with minimal depression were witnessed among participants who rarely consumed vegetables [16(13.1%) housewives and 50(42.4%) working women]. Considering overall depression, a large number of housewives showed moderate depression, i.e. 156(52%). On the contrary, the number of working women showing minimal depression was 142(47.3%) compared to 30(17.4%) housewives (p<0.001). CONCLUSIONS: Although housewives were more depressed than working women, the highest number of participants with none or minimal depression in both study groups were those who had better dietary practices.
Assuntos
Transtorno Depressivo/epidemiologia , Dieta/estatística & dados numéricos , Características da Família , Renda/estatística & dados numéricos , Mulheres Trabalhadoras/estatística & dados numéricos , Adulto , Estudos Transversais , Transtorno Depressivo/psicologia , Feminino , Humanos , Pessoa de Meia-Idade , Paquistão/epidemiologia , Questionário de Saúde do Paciente , Médicas/psicologia , Médicas/estatística & dados numéricos , Professores Escolares/psicologia , Professores Escolares/estatística & dados numéricos , Índice de Gravidade de Doença , Mulheres/psicologia , Mulheres Trabalhadoras/psicologiaRESUMO
OBJECTIVE: To compare awareness of osteoporosis and its associated risks among working women and housewives. METHODS: This cross-sectional study was conducted at Karachi University and Dow University of Health Sciences, Karachi, from January to April 2015, and comprised working women and housewives who were enrolled using convenience sampling. Data was collected on awareness, dairy, fruit, vegetable, poultry/fish consumption as well as exercise, diagnosis and treatment taken for deficiency of vitamin D. Weight, height and body mass index were noted. Analysis was done using SPSS 17. RESULTS: Of the 600 participants, 300(50%) were housewives and 300(50%) were working women. Significant differences were observed in marriage years, number of children and income (p <0.05). Body mass index of groups demonstrated that more working women were within normal range weight than housewives (p<0.05). Fewer housewives had awareness about osteoporosis and the majority of them had a sedentary lifestyle (p<0.001). More housewives were diagnosed with vitamin D deficiency and were prescribed for treatment (p<0.001). Dairy and vegetable consumption was found comparable while fruits and poultry/ fish intake was better in working women (p<0.05). Since the subjects in both groups had no regular exercise programme, therefore the overall results were insignificant (p>0.05). CONCLUSIONS: Greater number of working women had awareness of osteoporosis.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Osteoporose , Deficiência de Vitamina D , Mulheres Trabalhadoras/estatística & dados numéricos , Adulto , Estudos Transversais , Feminino , Humanos , Paquistão/epidemiologia , Fatores de RiscoRESUMO
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.
Assuntos
Índice de Massa Corporal , Dieta/métodos , Comportamento Alimentar , Estilo de Vida , Obesidade/prevenção & controle , Sobrepeso/prevenção & controle , Mulheres Trabalhadoras , Adulto , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Comportamento SedentárioRESUMO
OBJECTIVE: To identify major dietary patterns and examine their association with anthropometric, lifestyle and socio-economic factors among women belonging to different communities living in Karachi. METHODS: This cross-sectional study was conducted in Karachi from June 2014 to August 2015, and comprised women of Aga Khani, Dawoodi Bohra and Memon communities. Dietary data was collected through a 108-item food frequency questionnaire and dietary patterns were derived by factor analysis. Three dietary patterns were extracted: processed, mixed and traditional. SPSS 20 was used for data analysis. RESULTS: Of the 322 participants, 108(33.54%) belonged to the Aga Khani community, and 107(33.23%) each to Dawoodi Bohra and Memon communities. Moreover, 58(53.7%), 39(36.4%) and 25(23.4%) in the three groups, respectively, had a university degree. Besides, 44(40.7%) women belonging to the Aga Khani community were married, compared to 53(49.5%) and 37(34.6%) in Dawoodi Bohra and Memon communities. The mean factor loading for mixed food pattern was 0.24 among women of the Aga Khani community, whereas respective values for Dawoodi Bohra and Memon communities were 0.005 and -0.25. The mean factor loading for traditional pattern was 0.77 in the Dawoodi Bohra community, in contrast to -0.24 and -0.52 among women belonging to Memon and Aga Khan communities. Processed food pattern was negatively associated with age in the Aga Khani community (p<0.001) and Dawoodi Bohra community (p=0.010). Mixed food pattern was positively associated with family size in the Aga Khani community (p=0.007), with watching television for 1-3 hours (p=0.007) and higher family income in the Dawoodi Bohra community (p=0.009). Traditional food pattern depicted a positive association for watching television >1-3 hours/day (p=0.028) and total calorie consumption/day (p=0.008) in Dawoodi Bohra community. A negative trend was noted for watching television (1-3 hours/day p=0.020; >3hours/day p=0.004) and physical inactivity (p=0.039) in the Memon community. CONCLUSIONS: Lifestyle and socio-economic variables were found to be associated with dietary patterns in all communities.
Assuntos
Antropometria , Dieta , Estilo de Vida , Adulto , Estudos Transversais , Comportamento Alimentar , Feminino , Humanos , Paquistão , Fatores SocioeconômicosRESUMO
The present study aimed to characterize a biodegradable film produced from the polysaccharide of an indigenous plant Cordia myxa. Effect of plasticizer type (Glycerol, Sorbitol, PEG200 and PEG 400) and concentration (0-30 %) was studied on sorption and optical properties of the casted film. Increase in plasticizer concentration resulted in increase in equilibrium moisture content of the film and was supported by GAB model of sorption indicating that isotherms were of Type II. The monolayer value increased with the increase in plasticizer concentration with a peak of 0.93 g.g-1 for glycerol. Addition of plasticizers improved the total color (ΔE) with glycerol showing the highest effects. All films showed resistance to UV light in the range of 280-200 nm. The polysaccharide of the fruit of C.myxa can be used to prepare an edible film with improved properties as compared to other available edible coatings.
RESUMO
Performance of antioxidants is improved by incorporating them into polymer matrix such as polysaccharides based edible coatings. Gum cordia, an anionic polysaccharide extracted from the fruits of Cordia.myxa could be used as carrier of antioxidants by virtue of its strong adhering and emulsifying properties. This study aimed to explore the potential of gum cordia as carrier of antioxidants when applied as edible coating on peanuts. Gum Cordia was compared with carboxymethyl cellulose (CMC) in delivering of antioxidants: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and ascorbic acid (AA). Coated and uncoated peanuts were stored at 35 °C for 126 days and coating carrier effectiveness was measured by following lipid oxidation using chemical parameters (peroxide value and thiobarbituric acid reactive species) and sensory evaluation (oxidized flavor). Significant differences (p < 0.05) between coated and uncoated samples were observed. Gum cordia was found better than CMC to deliver the antioxidants. Gum cordia based coating in combination with BHA/BHT exhibited highest protection (290 % higher shelf life than control) based on peroxide value (40 meq.O2 kg(-1)) followed by gum codia plus BHT (244 %), gum cordia plus BHA (232 %), CMC plus BHA/BHT (184 %), CMC plus BHA (139 %), CMC plus BHT (119 %), gum cordia plus AA (96 %) and CMC plus AA (46 %).
RESUMO
The effects of water extractable pentosans (WEP) and water unextractable pentosans (WUP) on pasting properties in flours of eight different hard white spring wheat (HWSW) cultivars was studied. WEP and WUP isolated from a hard wheat flour were added to each of the cultivars at 1% and 2% level. The results indicated that WEP exhibited a pronounced effect on pasting properties as compared to WUP and variety. Univariate analysis of variance (ANOVA) was used to evaluate sources of variation. The variety significantly (P < 0.001) influenced all the pasting parameters. WUP caused significant (P < 0.001) variation in paste viscosities (except breakdown). WEP influenced more pronouncedly the hot paste, cold paste, breakdown and setback viscosities with F values-221.802, 214.286, 98.073 and 120.159, respectively. Variety-by-WEP interaction exhibited significant (P < 0.01) influence on pasting time, peak, hot paste and cold paste viscosities. Whereas, variety-by-WUP interaction only significantly (P < 0.001) influenced the pasting- time and -temperature. Duncan's test was used to analyze the significant difference (P < 0.05) within the variety. The results revealed that WUP did not induce significant (P < 0.05) influence on all the pasting parameters, whereas, WEP influenced significantly (P < 0.05) the paste viscosities of some of the varieties. It was also found that the addition of WEP remarkably reduced the setback, hot paste, cold paste viscosities and increased the breakdown viscosity in all cultivar flours. The effect of WEP was greater at higher level of supplementation on paste viscosities.
RESUMO
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.
Assuntos
Oryza , Oryza/química , Amido/química , Solubilidade , Viscosidade , Alimentos , AmiloseRESUMO
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.
Assuntos
Celulose/química , Sorghum/química , Zea mays/química , Celulose/análogos & derivados , Celulose/isolamento & purificação , Grão Comestível , Compostos de Epóxi , Reologia , Solubilidade , Amido/química , Amido/isolamento & purificação , Água/químicaRESUMO
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.
Assuntos
Citratos/química , Géis/química , Lactatos/química , Oryza/química , Amido/química , Água/química , Varredura Diferencial de Calorimetria , Elasticidade , Temperatura Alta , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Reologia , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/ultraestrutura , ViscosidadeRESUMO
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 (Gâ³) 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.
Assuntos
Ácido Cítrico/química , Grão Comestível/química , Sorghum/química , Amido/química , Zea mays/química , Amido/isolamento & purificaçãoRESUMO
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 (È â). 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.
Assuntos
Hordeum/química , Amido/química , Culinária , ReologiaRESUMO
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.
Assuntos
Reagentes de Ligações Cruzadas/química , Sorghum/química , Amido/análise , Amido/química , Resistência à Tração , Acetilação , Permeabilidade , ÁguaRESUMO
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.
Assuntos
Sorghum/química , Amido/química , Zea mays/química , Sequência de Carboidratos , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Difração de Raios XRESUMO
Pasting and functional properties of water chestnut starch (WCS) alone and mixture of WCS and xanthan gum (XG) were determined by addition of NaCl (0.5, 1, and 2%) at fixed water chestnut starch (5%) and xanthan gum (0.3%) concentration. Results indicated that presence of NaCl had a significant impact on functional and pasting properties of both WCS alone and WCS - XG mixture. Pasting temperature of WCS and WCS - XG mixture increased linearly with increasing salt content, whereas a reverse trend was observed in peak viscosity and sets back in case of WCS alone. It was found that addition of NaCl decreased the swelling power of WCS alone, while it increased in case of WCS - XG mixture. The water absorption of WCS - XG improved drastically by the addition of NaCl while a rapid decline in syneresis was observed with WCS - XG mixture. The transparency of both WCS and WCS - XG mixture were found to be increased after the addition of NaCl.
Assuntos
Fenômenos Químicos , Eleocharis/química , Polissacarídeos Bacterianos/química , Cloreto de Sódio/química , Amido/química , Fenômenos Químicos/efeitos dos fármacos , Polissacarídeos Bacterianos/ultraestrutura , Cloreto de Sódio/farmacologia , Solubilidade , Análise Espectral , Amido/isolamento & purificação , Amido/ultraestrutura , TemperaturaRESUMO
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 (3â¯g/100â¯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.
Assuntos
Compostos de Epóxi/química , Embalagem de Alimentos , Pennisetum/química , Amido/química , Acetilação , Glicerol/química , Permeabilidade , Solubilidade , Vapor , Temperatura , Resistência à Tração , Água/químicaRESUMO
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 1710-1727â¯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 (Gâ³). Both CWS and HWS starch citrates prepared by addition of 40â¯g citric acid to 100â¯g of starch exhibited highest G' and Gâ³ 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.
Assuntos
Citratos/química , Lactatos/química , Oryza/química , Amido/química , Álcoois/química , Álcalis/química , Reologia , Solubilidade , Água/químicaRESUMO
In the present study, modifications were done by varying concentration of citric and lactic acid (20â¯g and 40â¯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 1047â¯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 7â¯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.