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

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 μg 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. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Viña, Sonia Zulma. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Dini, Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

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

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

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

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

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

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

Evaluation of some important physicochemical properties of starch free grewia gum

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 α-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 ∼ 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

Recurrent Selection to Alter Grain Methionine Concentration and Improve Nutritional Value of Maize

Methionine is an essential amino acid that is limiting in maize- (Zea mays L.) based diets. The objective of this work was to determine whether we could alter grain methionine concentration in random-mated maize populations by mass selection for methionine concentration using a microbial assay. In one study, we developed two populations by selecting for high or low methionine concentration (HM or LM, respectively) for three generations starting from the random-mated population BS11. Grain from these populations was used to formulate diets for a feeding trial in which 15 rats were fed HM grain and 15 rats were fed LM grain. Rats on the HM diet had a 0.018 higher feed efficiency (g gain/g feed) than rats on the LM diet. In a second study, we performed three cycles of selection for high or low methionine concentration starting with two random-mated populations, BS11 and BS31. We evaluated each cycle of selection in a field trial with two replications in each of two years. Methionine concentration was significantly correlated with the cycle of selection, changing on average 0.004 g methionine/100 g grain per cycle. Kernel mass, %N, oil, protein, starch, tryptophan, and lysine concentration did not exhibit significant correlations with cycle of selection. We conclude that recurrent selection for grain methionine concentration using a microbial assay is an effective method to alter methionine content

Quality attributes of sweet potato flour as influenced by variety, pretreatment and drying method

The effect of pretreatment methods (soaking in water, potassium metabisulphite solution, and blanching) and drying methods (sun and oven) on some quality attributes of flour from ten varieties of sweet potato roots were investigated. The quality attributes determined were chemical composition and functional properties. Data obtained were subjected to descriptive statistics, multivariate analysis of variance, and Pearson's correlation. The range of values for properties of sweet potato flour were: moisture (8.06–12.86 ± 1.13%), starch (55.76–83.65 ± 6.82%), amylose (10.06–21.26 ± 3.92%), total sugar (22.39–125.46 ± 24.68 μg/mg), water absorption capacity (140–280 ± 26), water solubility (6.89–26.18 ± 3.80), swelling power (1.66–5.00 ± 0.50), peak viscosity (24.50–260.92 ± 52.61 RVU), trough (7.08–145.83 ± 34.48 RVU), breakdown viscosity (11.00–125.33 RVU), final viscosity (10.21–225.50 ± 60.55 RVU), setback viscosity (3.04–92.21 RVU), peak time (6.07–9.06 min) and pasting temperature (69.8–81.3°C). Variety had a significant (P 0.05) affect moisture, fat and lightness (L*). Drying method did not significantly (P > 0.05) affect fiber and L*. The interactive effect of variety, pretreatment and drying method had a significant (P < 0.001) effect on all the attributes except fat and fiber. Total sugar correlated significantly (P < 0.01) with water solubility (r = 0.88) of the flour samples. Variety was a dominant factor influencing attributes of sweet potato flour and so should be targeted at specific end uses

Exploitation of lettuce waste flour to increase bread functionality: effect on physical, nutritional, sensory properties and on consumer response

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The effect of bone choice on quantification of mineralization in broiler chickens up to 6 weeks of age

An experiment was conducted to assess the most appropriate bone type for measuring bone mineralization in male broiler chicks up to 42 d. A total of 72 male broilers were raised in 0.64 m2 pens on a litter floor. The study design included 2 dietary treatments (Control and Low) containing differing levels of total phosphorus (7.8 and 4.4 g/kg for Control and Low diets respectively) and calcium (22.7 and 13.1 g/kg for Control and Low diets respectively) with each fed to 6 replicate pens of 6 birds. Each wk, 6 birds per diet were euthanized and leg bones removed to measure ash percentage. Foot, toe, tibia, and femur ash were compared using the mean of both legs from each bird, via t-tests to separate Control and Low diets. At the end of wk 1, diets could not be separated using any of the bone ash measures. From wk 2 to wk 5, both tibia and foot ash differentiated between the Control and Low diets, and tibia continued to show significant differences between the diets into wk 6. Femur ash did not show any dietary differences until wk 3, but then showed significant differences between the diets until wk 6. Toe ash only differentiated between diets at wk 2, and variation both within and between birds was high, particularly with younger birds. These results suggest that bird age has implications when choosing a bone for assessing possible differences in dietary phosphorus and calcium uptake. Femur ash may be more appropriate for showing differences in broilers aged 6 wk and older. Foot ash provides a comparable alternative to tibia ash in birds aged 2 to 5 wk of age, providing a labor- and time-saving alternative

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

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 β-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)