Chemical composition and microbial evaluation of Argentinean Corrientes cheese

The chemical and microbial composition of an artisanal cheese made from raw cow's milk produced and consumed in the province of Corrientes (north-eastern Argentina) was evaluated using standard methods. Corrientes cheese has high moisture content (50–60%), normal protein and fat contents (21–27 and 22–26% respectively), and is low in salt (0.5–2.0% w/w). Microbial counts also varied significantly between samples (colony-forming units per gram ranges covering logs of 5–11), probably due to environmental contamination in the raw material. These results will help produce higher quality Corrientes cheeses with well-defined characteristics.     

RECOVERY OF ANTHOCYANINS, PECTIN, AND DIETARY FIBER FROM CULL LOWBUSH BLUEBERRIES

Cull lowbush blueberries are a potential industrial source of ingredients for the food and pharmaceutical industries. Pureed berries were extracted with ethanol acidified with 1, 3, or 5% (w/w) citric acid. Anthocyanins in the extract were determined spectrophotometrically; pectin and fiber were measured in the residue. More anthocyanins were extracted with 5% citric acid, with highest yields at 7 months’ postharvest. Total pectin increased from 3 to 7 months, but decreased at 9 months when 5% citric acid was used. Pectin esterification was influenced by acid level and storage time. Residual dietary fiber decreased over the 9 month storage period. These findings suggest that berries should be sorted for defects as soon as possible after freezing, then culls should be extracted within 6–7 months after harvest for optimal yields.     

Effect of Calcium Activated Protease (CAF) on Bovine Myofibrils Under Different Conditions of pH and Temperature

This study examined the in vitro effects of calcium-activated protease (CAF) on bovine myofibrillar proteins and structure under postmortem-like conditions of pH and temperature. Effects usually associated with this enzyme under optimal conditions were reduced as temperature and/or pH were lowered. However, significant activity remained at 15°C and pH 6.5, and some activity was detectable at even lower pH's and temperatures. Effects observed included: solubilization of myofibrillar protein, degradation of the myofibrillar protein titin and others, and an increase in the degree of myofibrillar fragmentation. These results suggest that CAF is able to hydrolyze proteins that are important to structural integrity under conditions mimicking those present in postmortem muscle.     

Hydrolysis and Ultrafiltration Treatment to Improve the Nutritive Value of Rapeseed Proteins

In order to improve their nutritive value, rapeseed proteins were hydrolyzed with pepsin (60 min) and trypsin (120 min). The hydrolysate was centrifuged at 10,000 ×g for 10 mln and the soluble fraction was ultrafiltered with a Romicon cartridge having a molecular weight cut-off of 10,000 daltons. Nutritional experiments with rats demonstrated that the net protein ratios obtained with rapeseed hydrolysate and ultrafdtrate (4.68 and 4.55 respectively) were higher (P < 0.05) than that of casein (4.40). The protein digestibility of the ultrafiltrate (90.3) was not different from that of casein (91.1) but higher than that of raw rapeseed flour (81.9). These hydrolysis and ultrafiltration treatments improved the nutritive value of rapeseed proteins by permitting the isolation of by-products of a molecular weight lower than 5000 daltons.