Freshness of fish in most markets was found to be the significant quality parameter. The state of fish freshness was assessed by various methods but most of them were costly, time-consuming and not user friendly tools which made the development of simple, easy, undemanding and reliable system for the evaluation of fish freshness unresolved goal. The findings of many researchers revealed that there was remarkable correlation between the pH and the fish freshness which suggested that this physical characteristic could be used as suitable tool for the analysis and fish freshness evaluation rather than sensory evaluation method which inherent many uncertainties. Based on this demand, this paper was established with the objective of reviewing the literature which focused on the pH as one of the simple and reliable freshness indicator for cold stored fish samples.

This study was a part of a research project aiming to investigate the texture characteristics of protein -starch interaction in fish based product keropok lekor. Accordingly, the current review study focused on some physicochemical (molecular weight, viscosity, chemical composition and swelling power) and thermorheological (gelatinization, retrogradation and viscoelsticity) characteristics of sago starch alone and in mixtures with other ingredients such as sucrose, salts and hydroclloids. The inferred outcome of this extensive survey revealed that the gelatinisation temperature for sago-water mixture ranged from 69.4-70.1°C which was low compared to sweet potato, tania and yam starches. The role of using hydrocolloids in starch-based foods was to control the rheological properties as well as modifying the texture of the products, enhaning or modifying the gelatinization and retrogradation behaviour and improving water-holding capacity of the system. In the presence of sucrose or sodium chloride, the gelatinisation temperatures of sago starch shifted to higher temperatures and its enthalpy decreased. The addition of salts caused an elevation or depression of gelatinization temperature and gelatinization enthalpy, depending on their types and concentrations used. However, sodium chloride appeared to exhibit a maximum inhibitory effect on starch gelatinisation at a concentration of 6-9%.

The chemical and taste characteristics of threadfin bream (Nemipterus japonicus) hydrolysate produced by Alcalase hydrolysis of the fish muscle (pH 8.5, 60 • C, 120 min, enzyme/substrate ratio 20 g kg −1 ) were studied. Umami, bitter and fishy were the dominant tastes. The bitter amino acids methionine, valine, isoleucine, phenylalanine, leucine and tyrosine comprised 317 mg g −1 of the total amino acids present. The umaminess could be due to the presence of high contents of glutamic acid and inosine 5 -monophosphate. SDS-PAGE analysis showed that the peptides in the hydrolysate had molecular weights ranging between 7.2 and 64 kDa.

This study was carried out to examine the changes in cocoa aspartic endoproteinase and carboxypeptidase activities, mass pH and temperature during 144 h (6 days) of fermentation using shallow wooden boxes. The results showed that at 72 h of fermentation, the activity of aspartic endoproteinase was higher than the original value. However, at 96 h the carboxypeptidase activity was higher than its original activity. The study also found a high correlation 0·99 (P<0·05) between the mass temperature with the aspartic endoproteinase at 48 h of fermentation. No correlation was found between the mass pH and temperature with the carboxypeptidase during fermentation. The degradation of vicilin‐class globulin was about 88·8% and that of albumin was 47·4% at the end of fermentation. © 1998 SCI.

The present work aims at finding an optimized explicit finite difference scheme for the solution of problems involving pure heat transfer from the surfaces of Pangasius Sutchi fish samples suddenly exposed to a cooling environment. Regular shaped packages in the form of an infinite slab were considered and a generalized mathematical model was written in dimensionless form. An accurate sample of the data set was chosen from the experimental work and was used to seek an optimized scheme of solutions. A fully explicit finite difference scheme has been thoroughly studied from the viewpoint of stability, the required time for execution and precision. The characteristic dimension (half thickness) was divided into a number of divisions; n = 5, 10, 20, 50 and 100 respectively. All the possible options of dimensionless time (the Fourier number) increments were taken one by one to give the best convergence and truncation error criteria. The simplest explicit finite difference scheme with n = (10) and stability factor (∆X) 2 /∆τ = 2) was found to be reliable and accurate for prediction purposes.