A starchy food that is initially a single-phase body turns into a multiphase body during boiling because of starch gelatinization. Fick's law is applicable only to a homogeneous system and is not applicable to such a multiphase system. Relative Water Content (RWC) model has been proposed as an alternative model that is able to describe water migration in multiphase food systems. In the RWC model, water migration is driven by the gradient of water content divided by the water holding capacity (WHC), m/m*. In this study a WHC profile (WHC plotted against water content with which starchy food is heat-treated) was assumed based on information concerning starch gelatinization. Using this WHC profile, the correlation between WHC profile and transient water content profile in a wheat flour dough slab during boiling was examined. A modified WHC profile was found to be applicable for describing certain characteristic features of the transient water content profile in a slab of wheat flour dough during boiling.

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.

In the present study, production and using possibilities of powder of macaroni boiling water (PMBW) were investigated. After cooking process of macaroni, firstly pre-drying was carried out at 50 °C in a drying oven and then lyophilization process was conducted to obtain final powder product. Physicochemical characterizations like total dry matter, ash, fat, protein, pH, aw and color properties were carried out and also technological properties of sample were determined. Both macaroni boiling water and the final powder product were examined in terms of microbiological analyses. It was found that macaroni boiling water had to be processed in 6 h after cooking if the cooking water was stored at room temperature. Also, the duration of 12 h after cooking was found to be limit level for microbiological safety of cooking water if it was stored at +4 °C. Besides, scanning electron micrographs of particles and fatty acid and mineral profile of the final powder product were determined. Macaroni boiling water is a by-product having a lot of nutrients and in this study it was proved that utilization of this by-product may be feasible. The macaroni boiling water can be used as a food ingredient and also as an enrichment agent.

Nylon 6 and nylon 12 food packaging materials used as sausage casings are typically exposed to fatty food on one side and boiling water on the other during the cooking process. To simulate the migration behaviour under these conditions, a special migration cell was constructed and filled with olive oil on one side of the polymer and water on the other to find out what amounts of the migrants will transfer to either side and phase at 100 °C. Results show that when a nylon 6 film is exposed to the conditions as described above, total mass transfer of the monomer—caprolactam—into the water phase occurs after 2 h at 100 °C. Nylon 12 sausage casings release similar amounts of their monomer—laurolactam—into both the aqueous and oil phase. An existing computer migration model was adapted to simulate the situation of simultaneous two-sided migration applying previously determined diffusion and partitioning coefficients. The suitability of the model was confirmed by experimental data.

A polymerase chain reaction (PCR) assay with two nested pairs of primers selected from conserved sequences within a 2.3 kb randomly cloned DNA fragment from the Salmonella typhimurium chromosome was developed. The nested PCR assay correctly identified 128 of a total of 129 Salmonella strains belonging to subspecies I, II, IIIb and IV. One strain of Salm. arizona (ssp. IIIa) tested negative. No PCR products were obtained from any of the 31 non-Salmonella strains examined. The sensitivity of the assay was 2 cfu, as determined by analysis of proteinase K-treated boiled lysates of Salm. typhimurium. The performance of the assay was evaluated for environmental water, sewage and food samples spiked with Salm. typhimurium. Water and sewage samples were filtered and filters were enriched overnight in a non-selective medium. Prior to PCR, the broth cultures were subjected to a rapid and simple preparation procedure consisting of centrifugation, proteinase K treatment and boiling. This assay enabled detection of 10 cfu 100 ml(-1) water with background levels of up to 8700 heterotrophic organisms ml(-1) and 10000 cfu of coliform organisms 100 ml(-1) water. Spiked food samples were analysed with and without overnight enrichment in a non-selective medium using the same assay as above. Nested PCR performed on enriched broths enabled detection of < 10 cfu g(-1) food. Variable results were obtained for food samples examined without prior enrichment and most results were negative. This rapid and simple assay provides a sensitive and specific means of screening drinking water or environmental water samples, as well as food samples, for the presence of Salmonella spp.

A rapid and sensitive assay was developed for detection of small numbers of Campylobacter jejuni and Campylobacter coil cells in environmental water, sewage, and food samples. Water and sewage samples were filtered, and the filters were enriched overnight in a nonselective medium. The enrichment cultures were prepared for PCR by a rapid and simple procedure consisting of centrifugation, proteinase K treatment, and boiling. A seminested PCR based on specific amplification of the intergenic sequence between the two Campylobacter flagellin genes, flaA and flaB, was performed, and the PCR products were visualized by agarose gel electrophoresis. The assay allowed us to detect 3 to 15 CFU of C. jejuni per 100 ml in water samples containing a background flora consisting of up to 8,700 heterotrophic organisms per ml and 10,000 CFU of coliform bacteria per 100 ml. Dilution of the enriched cultures 1:10 with sterile broth prior to the PCR was sometimes necessary to obtain positive results. The assay was also conducted with food samples analyzed with or without overnight enrichment. As few as less than or equal to 3 CFU per g of food could be detected with samples subjected to overnight enrichment, while variable results were obtained for samples analyzed without prior enrichment. This rapid and sensitive nested PCR assay provides a useful tool for specific detection of C. jejuni or C. coli in drinking water, as well as environmental water, sewage, and food samples containing high levels of background organisms.