Effect of precooking time and drying temperature on the physico-chemical characteristics and in-vitro carbohydrate digestibility of taro flour

Achu is a thick porridge obtained by cooking and pounding taro (Colocasia esculenta) corms and cormels in a mortar. This study was undertaken with the objective of producing precooked taro flour that can be used in the preparation of achu. Taro slices were precooked to times of 0, 20, 45 and 90 min and dried in an air convection oven at varying temperatures of 50, 60, 70 or 80 °C before milling into flour which was then analysed for its water absorption capacity (WAC), water solubility index, emulsion activity and stability, bulk density, foam capacity and least gelation concentration (LGC). Achu made from the flours were equally analysed for their relative penetrometric index, bulk density and colour. The results showed that precooking induced significant (P<0.05) decrease in foam capacity, penetrometric index, and increase in LGC, emulsion stability and WAC. The drying temperature also induces significant reduction in emulsion capacity and stability, penetrometric index, and increase in LGC, WAC. Long precooking time (>45 min) and drying temperature (>60 °C) induced significant reduction of the in-vitro carbohydrate digestibility of taro achu.     

Study of fuel insolubles: Formation conditions and characterization of copper compounds

The solids formed in the systems containing copper in different oxidation states, in the presence and absence of hexanoic acid and dodecanethiol, together and separately, at room temperature, were studied. The experiments were performed in a mineral oil matrix, free of sulfur compounds and metals; a diesel oil matrix; and the reagents alone, without any matrix. The deposits formed were analyzed by elemental analysis (EA), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and total copper by inductively coupled plasma-optical emission spectrometry (ICP-OES), for their identification and determination of the probable structures. In samples containing both hexanoic acid and dodecanethiol, when there is copper(I), anhydrous copper(II) hexanoate is preferentially formed, but in samples of copper(II), copper(II) mercaptate is formed first. In samples of metallic copper in mineral oil matrix, no deposit formations occur. In all cases in which deposits were formed, they were the same as in diesel oil matrix.     

The Food Choice Questionnaire: Factorial invariant over western urban populations?

To assess the degree of measurement invariance of the Food Choice Questionnaire (FCQ) across western urban populations, it was filled out by demographically comparable samples in Canada (163 English speaking students, original version), Belgium (Flanders, N = 176, Dutch translation), and Italy (N = 163, Italian translation). Reliability of the FCQ-scales was moderate to good, but sometimes differed from the normative values. Item analysis pinpointed items with skewed distributions and low item-total correlations. Subsequent confirmatory and exploratory factor analyses revealed a suboptimal fit for the FCQ-model in all samples, with small to considerable divergences from the original configuration. The findings do not support the generalizability of the FCQ’s factor structure, but suggest that its items and underlying constructs may have different connotations across western urban populations. Explanations for the lack of convergence in factor structure and implications for research are discussed.     

Factors affecting the acid gelation of sodium caseinate

Acid gelation, turbidity and particle size development of dispersions of sodium caseinate and other protein fractions were studied. Sodium caseinate dispersions became particulate prior to the onset of gelation. Casein particles had enhanced stability to gelation in the presence of sodium chloride. Removal of the hydrophilic part of the κ-casein molecule through renneting and acidification of the soluble sodium para-caseinate resulted in increased gelation pH. Removal of most of the κ-casein through ethanol fractionation of sodium caseinate resulted in an α_s1-β-fraction, which was markedly destabilised at higher pH values during acidification in the presence of sodium chloride. Preheated β-lactoglobulin/sodium caseinate dispersions had similar acid gelation profiles in the presence of sodium chloride with or without N-ethylmaleimide, suggesting that secondary thiol-disulphide interchange reactions between κ-casein and pre-heated β-lactoglobulin aggregates did not effect the gel point and final storage modulus in the short time-frame (120 min) of acidification. It was found that κ-casein and sodium chloride played a significant role in both particle development and subsequent stability of sodium caseinate dispersions on acidification.     

COMPARATIVE STUDY OF CHEMICAL COMPOSITION AND PHYSICOCHEMICAL PROPERTIES OF DEFATTED WHEAT GERM FLOUR AND ITS PROTEIN ISOLATE

Chemical composition and physicochemical properties of defatted wheat germ (WG) flour (DWGF) and protein isolate (DWGPI) were evaluated to determine their potential as food ingredients. Protein content of DWGF was 31.42% while that of DWGPI was 84.18%. Comparison of the amino acid composition to the Food and Agriculture Organization/World Health Organization reference pattern indicated that DWGF and DWGPI had well‐balanced amino acid profiles. Both of them were relatively rich in lysine, whereas cystine was lacking. The main mineral constituents of DWGF were potassium, magnesium and calcium, while sodium was the dominating element in DWGPI as a result of salt extraction. Concentrations of potassium, magnesium, calcium, manganese and zinc in DWGPI were significantly decreased because of alkaline extraction compared to those in DWGF. The elements copper and iron were higher in DWGPI than in DWGF. Total flavonoid content of DWGF was about 0.35 g rutin equiv/100 g, whereas that of DWGPI was lower (about 0.24 g rutin equiv/100 g). Compared to soybean protein isolate, DWGPI was easily digested by pepsin in vitro, while DWGF was comparatively indigestible. Nonreduced and reduced sodium dodecyl sulfate‐polyacrylamide gel electrophoresis analyses seem to show that interpolypeptide S‐S bonds were absent in the structure of WG proteins. DWGF and DWGPI shared four groups of bands: (1) 85–70 kDa; (2) 55–50 kDa; (3) 47–40 kDa; and (4) below 20 kDa.     

Preparation of metallic silver from Ag2S slurry by direct hydrogen reduction under hydrothermal conditions

Metallic silver has been prepared by direct hydrogen reduction of Ag₂S in basic slurry under hydrothermal conditions. The XRD pattern and SEM micrographs of the reaction product are given. Metallic silver was predominant in the reduction product obtained by using ZnO as additive and PdCl₂ as catalyst at 220 °C, pH 12.0 and 2–3 MPa of partial hydrogen pressure for 4 h.     

The Cold Chain,one link in Canada’s food safety initiatives

The Cold Chain has always played an important role in food safety within the global market. The Canadian government has recognized it has an important role in the food continuum. In partnership with industry, national voluntary enhanced food safety systems, based on Codex Alimentarius (HACCP) principles, are being developed within Canada. These efforts will contribute towards food safety and will build confidence in foodstuffs grown, prepared and sold at all levels of trade and abroad.     

Evaluation of landscape and instream modeling to predict watershed nutrient yields

The project goal was to loosely couple the SWAT model and the QUAL2E model and compare their combined ability to predict total phosphorus (TP) and NO₃-N plus NO₂-N yields to the ability of the SWAT model with its completely coupled water quality components to predict TP and NO₃-N plus NO₂-N yields from War Eagle Creek watershed in Northwest Arkansas. Model predictions were compared using a statistical approach to identify significant differences between the two modeling methods. Results from two variations of the Pearson product-moment correlation (p < 0.05) indicated that correlation coefficients and regression slopes for the two data sets were not significantly different. This implies that neither modeling method was significantly better in predicting monthly TP and NO₃-N plus NO₂-N yields from the watershed. Additionally, no significant differences were present between predicted outputs of the SWAT model with instream components active compared with when instream components were inactive, indicating a need for further testing and refinement of the SWAT algorithms simulating instream processes. We can further infer that the instream processes available in SWAT may not be enhancing its predictive abilities as far as simulating instream components.