20,499 research outputs found

    Root starches enriched with proteins and phenolics from Pachyrhizus ahipa roots as gluten鈥恌ree ingredients for baked goods

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    Ahipa is a gluten-free starchy root, bearing phenolics and a protein content of ~9% db. Ahipa proteins are hydrosoluble, thus they are lost during starch extraction. The aim of this work was to recover ahipa proteins by isoelectric point (pI) precipitation to enrich ahipa and cassava starches. Both enriched starches had protein contents of ~2%, and their ATR-FTIR spectra revealed bands characteristic of ahipa proteins. Enriched starches also contained phenolics in concentrations of 18-20 渭g GAE/g. Enrichment lowered the whiteness index, but it remained higher than 90. Protein-enrichment did not modify gelatinization onset and peak temperatures but reduced the gelatinization enthalpy of ahipa starch. Enriched starches produced less-rigid buns than the native ones, with smaller and more homogeneously distributed alveoli in the crumb which resulted darker than the crust. Starch slurries acidified to the pI of ahipa proteins led to novel gluten-free ingredients by an easy, low cost processFil: Malgor, Martina. Provincia de Buenos Aires. Gobernaci贸n. Comisi贸n de Investigaciones Cient铆ficas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Centro Cient铆fico Tecnol贸gico Conicet - La Plata. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos; ArgentinaFil: Vi帽a, Sonia Zulma. Provincia de Buenos Aires. Gobernaci贸n. Comisi贸n de Investigaciones Cient铆ficas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Centro Cient铆fico Tecnol贸gico Conicet - La Plata. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos; ArgentinaFil: Dini, Cecilia. Provincia de Buenos Aires. Gobernaci贸n. Comisi贸n de Investigaciones Cient铆ficas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Centro Cient铆fico Tecnol贸gico Conicet - La Plata. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos; Argentin

    The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization

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    There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed one of two experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d post hatch. Dietary Ca content had no significant effect on in situ pH, but it contributed towards variance in ex situ pH of both gizzard and duodenum digesta

    Yellow pea flour and protein isolate as sources of antioxidant peptides after simulated gastrointestinal digestion

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    Although peas are widely consumed legumes throughout the world, the bioactivity ofthe peptides released by the gastrointestinal digestion has not been sufficiently studiedso far. The objective of the present work was to evaluate the potential of floursand protein isolates obtained from two varieties of yellow peas as sources of antioxidantpeptides. Flours and protein isolates were prepared and submitted to a simulatedgastrointestinal digestion. Protein hydrolysis degree (TNBS method) andprotein solubility (in phosphate buffer saline, pH = 7.4) values were independent onthe starting material. Antioxidant activity measured by oxygen radical absorbancecapacity (ORAC) and hydroxyl radical averting capacity (HORAC) showed no differencesbetween varieties. A lower activity was registered for protein isolates withrespect to flours in the case of HORAC, which could be associated with a loss of moleculeswith molecular masses lower than 43 kDa in the protein isolates. A significantincrease in activities was evidenced by both methods after gastrointestinal digestion,except in the case of HORAC activity of flours. Digested from protein isolates presenteda greater ratio of molecules smaller than 1.4 kDa and a lower ratio of thoselarger than 6.5 kDa with respect to digested flours, according to electrophoresis andgel filtration chromatography studies. Results suggested that the presence of othercomponents or/and the initial state of proteins would affect proteolytic attack ofdigestive enzymes. Both, pea flours and protein isolates, present interesting potentialas antioxidants food ingredients.Fil: Cipollone, Mar铆a Agustina. Provincia de Buenos Aires. Gobernaci贸n. Comisi贸n de Investigaciones Cient铆ficas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Centro Cient铆fico Tecnol贸gico Conicet - La Plata. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos; ArgentinaFil: Tironi, Valeria Anahi. Provincia de Buenos Aires. Gobernaci贸n. Comisi贸n de Investigaciones Cient铆ficas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Centro Cient铆fico Tecnol贸gico Conicet - La Plata. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaci贸n y Desarrollo en Criotecnolog铆a de Alimentos; Argentin

    Tunnel dryer and pneumatic dryer performance evaluation to improve small-scale cassava processing in Tanzania

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    In sub-Saharan Africa, cassava is grown by smallholder farmers and is the principal source of calories for the local population. However, the short shelf life of cassava associated with poor infrastructure in the region results in significant postharvest losses. The expansion of small-scale cassava processing could reduce these losses, but the availability of drying equipment suitable for use in such operations is limited. The objective of this research was to contribute to the development of cassava dryers suitable for use by smallholder farmers. A tunnel dryer and a pneumatic dryer being operated in Tanzania were evaluated using mass and energy balance analysis. It was found that the energy efficiency of the tunnel dryer was 29% and of the pneumatic dryer 46%. For the tunnel dryer, most of the heat losses were through unsaturated exhaust air, while for the pneumatic dryer, most losses were through radiation and convection. Practical Applications: In this study, a tunnel dryer and a pneumatic dryer suitable for use by smallholder farmers were evaluated during processing centers' usual cassava drying operations. The sources and extent of heat losses were identified, and then guidelines developed on how to reduce such losses. For both dryer types, improvements to the thermal insulation used could reduce heat losses to the ambient. For the tunnel dryer, decreasing the air mass flow rate by 57% would help to minimize exhaust heat losses without producing condensation inside the unit. For the pneumatic dryer, air mass flow rate could be reduced by 9%, improving energy performance without having a negative impact on the pneumatic conveying of the product. Those two modifications would be easy to implement and represent a significant contribution to the development of small-scale cassava drying technology

    Valorization of sweet corn (Zea mays) cob by extraction of valuable compounds

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    The main objective of this study was to investigate the proximate, mineral and phytochemical compositions of sweet corn cob (SCC), often neglected and regarded as agricultural waste. Compositional analysis showed that more than 60% of SCC was composed of insoluble dietary fibre, with cellulose being the major constituent. Results also showed that SCC can be a good source of non-essential protein and minerals (phosphorus,potassium and manganese). SCC had a total phenolic content of 6.74 g GAE kg-1 dry weight DW), of which bound phenolics were predominant. The bound phenolics fraction showed the highest antioxidant capacity in all three antioxidant capacity assays (TEAC, FRAP and DPPH) and contained the highest amount of ferulic and p-coumaric acid. The main carotenoids present in SCC were 尾-carotene, zeaxanthin and lutein. This investigation shows that SCC can be a potential source of natural colorant (carotenoids), antioxidants (phenolics)and nutritional supplements (proteins and phytochemicals)

    Association of index of welfare and metabolism with the genetic merit of holstein and simmental cows after the peak of lactation

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    The study investigated the relationship of markers of welfare and metabolism in milk, urine and blood with the genetic merit of Holstein and Simmental cows after the peak of lactation. Cows were selected from 3 Simmental (IS) and 2 Holstein (IH) commercial dairy farms. Within each farm, cows were ranked according to the estimated breeding value for milk protein yield (EBVp) from minus to positive and selected every 5 EBVps from minus to positive values (about 20% lactating cows for each farm). Milk was sampled and analysed for protein, fat, lactose, cortisol contents and somatic cell count (SCC). Blood and urines were analysed for biomarkers of metabolism and welfare. Significantly lower body condition score (BCS) was observed for IH in comparison to IS. Plasma creatinine was higher in IS, whilst Zn, total antioxidant status and glutathione peroxidase was higher in IH. The creatinine N to N ratio in urine was significantly higher for IS, while the purine derivatives (PD) N to creatinine N ratio was higher for IH. The EBVp was negatively related to BCS and glucose for IS and to plasma b-hydroxybutyrate in both breeds. EBVp was negatively Related to urinary PD N to total N ratios for IS and to PD N to creatinine N ratio for IH. These preliminary results would indicate that the selection of cows for milk protein yield had minor effect on plasma and milk biomarkers of welfare. Instead, biomarkers of metabolism were more affected by breed and genetic merit

    Evaluation of some important physicochemical properties of starch free grewia gum

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    Gums obtained by extraction from the inner bark of stems can be found in association with starch, which must be digested in order to obtain a refined polysaccharide isolate. In the present study, grewia gum obtained from the inner bark of the stems of Grewia mollis was shown to co-exist with starch and the effect of starch digestion on the physicochemical properties of the resultant polysaccharide was evaluated. The gum was extracted by maceration of the inner bark in deionized water and isolated by a combination of filtration, centrifugation and finally precipitation with absolute ethanol to produce the crude grewia gum extract (GG). The presence and content of starch in the gum sample was determined followed by enzymatic digestion of the starch using 伪-amylase (Termamyl 120L) to give a starch-free extract (GGDS). Physicochemical properties of the extracts such as total carbohydrates, total protein, differential sugar composition, NMR, intrinsic viscosity and rheological behaviour of the samples were evaluated. The GG extract had total carbohydrate content of 鈭 60 % out of which 11.8 % was starch, and a protein content of 2.3 %. Samples also contained galacturonic and glucuronic acid which were highly acetylated. Both samples had a higher proportion of galacturonic acid than glucuronic acid and contained rhamnose, arabinose, galactose, glucose and xylose as neutral sugars in varying proportions. Rheological measurements on 2 %w/w dispersions of the extracts show minor differences between both the original extract and the de-starched material but were influenced by changes in pH

    How isomaltulose and oligofructose affect physicochemical and sensory properties of muffins?

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    This is the peer reviewed version of the following article: Castell贸, ML, Echevarr铆as, A, Rubio-Arraez, S, Ortol谩, MD. How isomaltulose and oligofructose affect physicochemical and sensory properties of muffins J Texture Stud. 2021; 52: 410-419, which has been published in final form at https://doi.org/10.1111/jtxs.12602. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] This article analyses, the replacement of sucrose in muffins with nine different combinations of isomaltulose and oligofructose. Being a structural isomer of sucrose with approx. 50% of sucrose sweetness, isomaltulose is non-cariogenic and with a low glycemic profile but having the same calories as sucrose. Oligofructose is composed of fructose polymers, with a reduced caloric value and prebiotic effect. Specifically, height, percentage of alveoli, water content, A(w), mechanical, and optical properties have been measured along with a sensory evaluation. The results showed that all combinations of sweeteners gave place to softer muffins than control ones. Moreover, isomaltulose caused a darkening of the products likely due to an enhancement of the Maillard reactions. The highest amount of isomaltulose and the absence of sucrose meant the worst score in sweetness and flavor due to the low sweetening powder of isomaltulose.GENERALITAT VALENCIANA, Grant/Award Number: AICO/2017/043Castell贸 G贸mez, ML.; Echevarr铆as, A.; Rubio-Arraez, S.; Ortol谩 Ortol谩, MD. (2021). How isomaltulose and oligofructose affect physicochemical and sensory properties of muffins?. Journal of Texture Studies. 52(3):410-419. https://doi.org/10.1111/jtxs.12602S41041952

    Modeling drying kinetics of thyme (thymus vulgaris l.): theoretical and empirical models, and neural networks

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    [EN] The drying kinetics of thyme was analyzed by considering different conditions: air temperature of between 40 C and 70 C, and air velocity of 1 m/s. A theoretical diffusion model and eight different empirical models were fitted to the experimental data. From the theoretical model application, the effective diffusivity per unit area of the thyme was estimated (between 3.68 10 5 and 2.12 10 4 s 1). The temperature dependence of the effective diffusivity was described by the Arrhenius relationship with activation energy of 49.42 kJ/mol. Eight different empirical models were fitted to the experimental data. Additionally, the dependence of the parameters of each model on the drying temperature was determined, obtaining equations that allow estimating the evolution of the moisture content at any temperature in the established range. Furthermore, artificial neural networks were developed and compared with the theoretical and empirical models using the percentage of the relative errors and the explained variance. The artificial neural networks were found to be more accurate predictors of moisture evolution with VAR 99.3% and ER 8.7%.The authors acknowledge the financial support from the 'Ministerio de Educacion y Ciencia' in Spain, CONSOLIDER INGENIO 2010 (CSD2007-00016).Rodr铆guez Cortina, J.; Clemente Polo, G.; Sanju谩n Pellicer, MN.; Bon Corb铆n, J. (2014). Modeling drying kinetics of thyme (thymus vulgaris l.): theoretical and empirical models, and neural networks. Food Science and Technology International. 20(1):13-22. https://doi.org/10.1177/1082013212469614S132220
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