Improvement of Thiamin Retention in Canned Low-Acid Foods Through pH Adjustment

The effect of pH adjustment, in the range 5.0–6.9, on the thiamine retection after thermal processing of canned pea, corn, pork and beef liver pureés was studied. In all foods tested, reduction of pH, in the range studied, dramatically increased the retention of thiamin after processing. Retention of thiamin in processed pea and corn purees adjusted to pH 5.6 increased by 95% and 63%, respectively, as compared to samples having normal pH (6.9 for pea and 6.5 for corn).     

PLL-based digital control with Åstrom-Hägglund tuning

Digital control based on a phase-locked loop technique is presented. The key to this control is up/down counting. A dynamical model is given which links up/down counting with integrative control. The addition of proportional-derivative or similar algorithms is suggested to improve the control performance. A variation of the Åström-Hägglund methods is developed as a tuning procedure. Some comments are made on the sampling effects     

Chemical and Nutritional Characterization of Lupine Tempeh

Chemical composition and protein value of a tempeh-related food using lupine as substrate was determined. Bitter lupine grits were slowly degraded as compared to sweet lupine, pointing out the inhibitory action of lupine alkaloids. Any fungal degradation of the latter could be determined. Sweet lupine tempeh was further characterized. Water-soluble substances increased during the first 17 hr and then only slight changes occurred. The lipid fraction was preferentially metabolized by the fungus, reaching almost 50% loss after 45 hr fermentation. Linolenic and erucic acids were particularly degraded. No significant increase of the NPR values or protein digestibility of fermented lupine were observed. Preliminary results of sensory evaluation of deep-fat fried lupine tempeh were promising.     

Spray‐drying for the production of dried cultures

This review emphasises the importance of spray‐drying as an under‐used but promising technique to preserve viable and active starter cultures and also, potentially, probiotic cultures. The knowledge concerning the production of spray‐dried starter cultures is discussed. Different drying techniques and micro‐organisms have been investigated for their survival through the drying process. During drying and subsequent storage in the dried state, bacteria are subjected to several stresses, which have already been described as causing damage to cells, leading to the loss of cellular viability and activity. Some studies found that several factors/strategies can confer improved cellular viability.     

EFFECTS OF CORN MEAL, VITAL WHEAT GLUTEN, HIGH AMYLOSE STARCH AND EXTRUSION PARAMETERS ON TECHNOLOGICAL PROPERTIES OF WHEAT-BASED EXTRUDED BREADING

A wheat‐based extruded breading was produced using a Brabender single‐screw laboratory scale extruder (model GNF 1014/2) and applied to chicken nuggets. Response surface methodology was applied to study and optimize the effects of formulation and extrusion parameters on pick up, texture, solid loss, oil absorption and adhesiveness of fried coated nuggets. An optimized extruded breading was produced at 160C, 27% moisture content, 15% vital wheat gluten, 8% high amylose starch and 30% corn meal. The product showed pick up of 29.87%, adhesiveness of 100%, texture of 166.1 g, oil absorption of 2.97% and solid losses of 0.0885 absolute. The product presented similar values of pick up and adhesiveness, better texture, lower oil absorption and higher solid loss during deep‐frying, compared with commercial breadings. Acceptance test showed that the product had better overall appearance and fairly similar texture, compared with the commercial ones.     

Loss of available lysine during processing of different dulce de leche formulations

Dulce de leche is a dairy-based confectionery product prepared by heat concentration of milk and sugar, which can be partially replaced by other sugars. The effect of different formulations commonly used in the manufacture of this product on the rate of available lysine loss by Maillard reactions was examined. The replacement of 10% of sucrose by glucose increased by 90% the rate of lysine glycation, while the rise with fructose was only 30%. The use of skim milk led to a low fat product with the same available lysine content as the traditional one. Dulce de leche prepared with lactose-hydrolysed milk had a very low available lysine value.     

The effect of inulin as a prebiotic on the production of probiotic fibre-enriched fermented milk

We investigated the effect of inulin as a prebiotic on the production of probiotic fibre-enriched fermented milk. The kinetics of acidification of inulin-supplemented milk (0, 0.01, 0.02 and 0.04 g/g), as well as probiotic survival, pH and firmness of fermented milk stored at 4°C for 24 h and 7 days after preparation were examined. Probiotic fibre-enriched fermented milk quality was influenced both by the amount of inulin and by the co-culture composition. Depending on the co-culture, inulin addition to milk influenced acidification kinetic parameters, probiotic counts, pH and the firmness of the product.