The objective of this study was to determine the changes in water activity and moisture content in the dry fermented sausages Herkules, a typical multicomponent food, during ripening and storage. The sausages were made with lean beef, lean pork, pork fat, nitrite salt mixture, and sugars, and fermented with two starter cultures (Pediococcus pentosaceus + Staphylococcus carnosus and S. carnosus + S. xylosus + Lactobacillus farciminis). The samples were taken and tested during ripening (21 days) and storage (91 days). The water activity was measured by indirect manometric method in a static environment, the moisture content by halogen dryer. The water activity and moisture content decreased considerably, but very irregularily during the ripening, whereas they declined only slowly and linearly during the storage. The decrease during the storage was expressed by mathematical equations describing the changes of water activity and moisture content in function of the time. The use of different starter cultures had no influence on the two variables studied.

Ein beachtlicher Teil unserer Lebensmittel wird in der Lebensmittelindustrie, in Gross- und Kleinkuechen mit heisser Luft waermebehandelt. Nahrungsmittel sind oft hitzeempfindlich und veraendern ihre physikalischen, chemischen, stukturellen oder mikrobiologischen Eigenschaften waehrend der Hitzebehandlung. Dies beeinflusst sowohl die Qualitaet als auch den Naehrwert der entsprechenden Lebensmittel. Ferner ergibt sich oft ein Verlust an Wasser oder anderen Lebensmittelinhaltsstoffen. So betraegt der Wasserverlust beim Backen von Brot 15 bis 20 % und beim Kochen von Fleisch bis zu 30 %. Es werden die Mechanismen des Stoff-Transports, die Eigenschaften des Lebensmittels, die in diesem Zusammenhang von Bedeutung sind, sowie einige Beispiele fuer Qualitaets- und Naehrwertveraenderungen, die waehrend der Verarbeitung auftreten, diskutiert.

The production of protein hydrolysate from shrimp cooking water using enzyme Neutrase 0.5L was studied. Variations of enzymatic hydrolysis conditions consisted of enzyme concentration at 0, 0.5, 1.0, 1.5 and 2.0 % V/V; pH 5.5, 6.5 and 7.5; temperature 50, 55 and 60 deg C; and the hydrolysing time; 15, 30, 45, 60, 75 and 90 minute. The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mg N/ml were 0.5 % Neutrase, pH 6.5, 50 deg C and 30 minute. The hydrolysate was dried by freeze-drying. The dried product had dark brown color with considerable shrimp flavor and absorbed moisture quite readily. The product contained 3.80 % moisture, 51.89 % protein, 6.57 % fat, 24.76 % ash and 12.99 % carbohydrate. Sensory evaluation on the color and shrimp odor of dried product comparing to the freeze dried unhydrolysed cooking water product showed that the freeze-dried hydrolysate obtained higher scores in color and odor. However, sensory evaluation of the products after dissolving in water revealed that neither the hydrolysated nor unhydrolysed products had the significant differences in color, shrimp odor, sweet taste, bitter taste and overall flavor.

Production of protein hydrolysate from shrimp precooking water using enzyme Nutrase 0.5 L was studied. Variations in the enzymatic hydrolysis were composed of the quantity of enzyme (0, 0.5, 1.0, 1.5 and 2.0 percent v/v), the pH (5.5, 6.5 and 7.5), the hydrolysing temperature (50, 55 and 60 deg C) and the hydrolysing time (15, 30, 45, 60, 75 and 90 min). The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mgN/ml was 0.5 percent Nutrase, pH 6.5 50 deg C and 10 min. The chemical composition of the hydrolysate produced was 94.51 percent moisture, 2.52 percent protein, 0.33 percent fat, 1.77 percent ash and 0.88 percent carbohydrate. The hydrolysate was then freeze-dried. The dried product absorbed moisture quite easily and contained 3.80 percent moisture, 51.89 percent protein, 6.57 percent fat, 24.76 percent ash and 12.99 percent carbohydrate. To improve the quality of the dried product, the hydrolysate was mixed with 20 percent maltodextrin solution until the mixture had 10 percent total soluble solid before freeze-drying. It was found that the dried product absorbed moisture less rapidly and was ground easily. The composition of the improved product was 5.23 percent moisture, 36.98 percent protein, 3.71 percent fat, 16.61 percent ash and 41.98 percent carbohydrate. Sensory evaluation on the color and shrimp odor of these two dries products comparing to the freezed-dried unhydrolysed precooking water products showed that the freezed-dried hydrolysate without maltodextrin solution obtained the highest scores in color and odor. However, sensory evaluation the products after dissolving in water revealed that neither the hydrolysed nor unhydrolysed products had the significant differences in color, shrimp for, sweet taste, bitter taste and overall flavor.

External corrosion of tinplate cans containing food products, although less frequent and comparatively less dangerous than internal corrosion, should anyhow be studied more in depth, since the consumer requires not only high-quality products, but also cans having a good appearance. The objective of this experimental work was to study the influence of the main ions present in cooling waters on the corrosion of metal food cans. After a short introduction on tinplate corrosion phenomena and on the chemical and processing factors affecting it, the results are shown which were obtained from electrochemical corrosion trials performed using model solutions at various concentrations as well as cooling water samples directly taken from food plants. This research work yielded information on the corrosion mechanisms (extent and morphology) of the various species and parameters affecting the aggressivity of industrial waters (presence of additives, free chlorine content and conductivity) | La corrosione esterna delle scatole di banda stagnata contenenti prodotti alimentari, sebbene meno frequente e relativamente meno pericolosa della corrosione interna, deve comunque essere oggetto di maggiore attenzione, in quanto il consumatore richiede, oltre a prodotti di alta qualita', contenitori di aspetto accettabile. Oggetto del lavoro sperimentale e' stato lo studio dell'influenza dei principali ioni presenti nelle acque di raffreddamento sulla corrosione delle scatole metalliche per alimenti. Dopo una breve introduzione sui fenomeni di corrosione della banda stagnata e sui fattori chimici e di processo che la condizionano, il lavoro illustra i risultati ottenuti nelle prove di corrosione elettrochimiche effettuate con soluzioni modello a diverse concentrazioni e con acque di raffreddamento prelevate direttamente presso industrie alimentari. A conclusione della ricerca sono state ottenute informazioni sul meccanismo di corrosione (intensita' e morfologia) delle diverse specie e sui parametri che influenzano l'aggressivita' delle acque industriali (presenza di additivo, concentrazione di cloro libero e conducibilita')

The effect of diet water content on the growth, cocoon quality and food utilization of the silkworm was investigated. The body weight of mature larvae increased greatly as the water content increased, and the weight increase was mainly due to the increase of water content of larvae. The diet water content was less effective on the water content of pupae than on that of mature larvae. The water content of feces increased progressively as the fifth-instar larvae grew, especially in the larvae fed with diets having high contents of water. The suitable water content in the diet ranged from 60 to 65% for the cocoon quality, although it was found to be somewhat different between the 2 silkworm races used. On the basis of the above results, we tried to make a new type of artificial diet for the silkworm