The influence of chemical and biological acidification on dough rheological properties and bread quality has been investigated. Two different flour types were used. Dough was chemically acidified with lactic acid. Two types of biologically acidified dough were prepared: dough with dry sourdough and with a Lactobacillus brevis preferment. Wheat dough rheological properties were investigated using the Farinograph, Extensograph and Amylograph. The baking response was also determined using standard baking tests. Addition of acidifiers resulted in firmer doughs with less stability, decreased extensibility and decreased gelatinisation maximum. The biological acidifiers increased the bread specific volume. Lactic acid addition had no influence on bread specific volume. In general, biological and chemical acidification decreased bread hardness. The addition of dry sourdough significantly decreased the lightness and increased the yellowness and redness of the bread crumb. The crust chroma, hue angle and brownness index were significantly changed by addition of acidifiers. * Values are mean ± SD of four independent determinations; mean values followed by common letter within the same column are not significantly different (P < 0.05). † Control, control dough; I and II, flour types: T-550 and T-110, respectively; LAB, biologically acidified dough by addition of sourdough prepared with Lactobacillus brevis L-75; DS, biologically acidified dough by addition of dry sourdough; LA, chemically acidified dough by addition of lactic acid. Properties of acidified bread D. K. Komlenić et al.

Product colour is one of the most important criteria for determining pasta quality. For pasta produced without eggs, pasta colour will depend mostly on the content of the yellow pigment in flour. Analyses were done with 12 samples of hand-made pasta without eggs. The yellow pigment content was determined by the standard spectrophotometric method, while the pasta colour (fresh shaped and dry milled pasta) was measured using the Minolta CR-300 colorimeter. The results obtained show that there is a correlation between spectrophotometric determination of the yellow pigment content and the results of colorimetric measurement. The correlation coefficient between the colorimetric results of dry milled pasta and the yellow pigment content is higher than that between the colorimetric results of fresh shaped pasta and the yellow pigment content.

Ugarčić-Hardi Ž., Jukić M., Koceva Komlenić D., Sabo M., Hardi J. (2007): Quality parameters of noodles made with various supplements. Czech J. Food Sci., 25: 151-157.The influence of various supplements (extruded maize, maize, defatted soy flour and maize/soy flour blends, lecithin and wheat straw) on the pasta quality has been examined. Noodles were prepared by means of conventional laboratory equipment. Common wheat flour supplemented with 1% lecithin powder, 20% extruded maize flour, 20% maize flour, 10% defatted soy flour, 20% defatted soy and maize flour blend (1:1), and 7.5% wheat straw was used. The produced pasta was dried at 55°C in a laboratory dryer (Instrumentaria, Croatia) to 13.0% moisture. Pasta colour was evaluated with fresh pasta by measuring L*, a*, b* parameters by means of a reflectance colorimeter (CR 300 Chroma-metter, Minolta, Japan). The following parameters of cooked noodles were determined: volume increase coefficient, water uptake (g/g), optimum cooking time (min), and cooking loss (%). Sensory quality was evaluated on a scale of 1-5 for: odour, external appearance, flavour and mouth feel, and total quality scores. The noodles made with extruded maize flour, maize flour, and wheat straw supplements had the highest total sensory score. Cooking losses of these samples were below 10%. Regardless of the fact that the sample with lecithin had the lowest cooking loss, it was not acceptable for the panel members. Supplementation with extruded maize, maize and defatted soy flours, and wheat straw could be used to produce pasta without eggs, with a reduced cholesterol content, enriched with dietary fibre and possessing a lower glycemic index.

Changes in chemical composition, grain quality parameters, oxidoreductase and exopeptidase activities of wheat grains infested by Sitophilus granarius were monitored during 1 year of storage. Significant increase in flour titratable acidity of infested grains occurred by day 90. Subsequently, infestation was followed by decrease of grain hectoliter weight on day 180, decrease of carboxypeptidase activity on day 240, polyphenol oxidase and catalase activities increased and total starch decreased on day 270, while significant changes of total protein content, extractable protein concentration, phenylalanyl-aminopeptidase and Zeleny sedimentation occurred between 300 and 360 days of storage. The data indicate that S. granarius infestation influenced chemical composition, quality parameters, as well as oxidoreductase and exopeptidase activity in wheat grains, but the extent of these changes was mostly detectable at higher levels of grain infestation. Among the examined parameters, flour titratable acidity and carboxypeptidase activity showed potential to be used as early indicators of grain infestation. PRACTICAL APPLICATIONSGranary weevil, S. granarius, is one of the major grain-damaging insects. This primary infester feeds on grains as adult, or on grain endosperm as larvae causing significant economic losses, due to unsuitability of damaged grains for human food production. Although various methods of S. granarius detection in stored grains have been applied worldwide, there is still a need for cheap indicative methods for detecting insect infestation. This study investigating changes in chemical composition, quality parameters, oxidoreductase and exopeptidase activities during temporal development of infestation by S. granarius shows that flour titratable acidity and carboxypeptidase activity could be used as early indicators of wheat grain infestation. bs_bs_banner Journal of Food Biochemistry ISSN 1745-4514

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