Abstract:
This research aimed to study the processing of abalone Haliotis asinina L. in brine in retort pouch. Initially, the effect of handing temperature (0[degrees Celsius] and 10[degrees Celsius]) on raw material (whole abalone and shelled-off gutted abalone) quality was studied. As storage time increased, the pH of abalone changed slightly. The firmness of abalone stored at 0[degrees Celsius] and 10[degrees Celsius] tended to decrease. The shelled-off gutted abalone had a better texture quality than whole abalone. Aerobic bacteria count reached 6 log cfu/g when storing shelled-off gutted abalone and whole abalone at 0[degrees Celsius] for 6 and 9 days, respectively, and at 10[degrees Celsius] for 3 and 4 days, respectively. Histidine decarboxylase producing bacteria and histamine were not found in abalone stored in all conditions. The effect of heating process was also studied by heating abalone at 80[degrees Celsius], 100[degrees Celsius], and 120[degrees Celsius] for 2-240 minutes. As heating temperature and time increased, the cooking loss and degree of browning of abalone tended to increase. Heated abalone at 100[degrees Celsius] and 120[degrees Celsius] had more degree of browning compared to that at 80[degrees Celsius]. A significant increase in browning was observed when heating abalone at 100[degrees Celsius] for 60 minutes and 100[degrees Celsius] for 20 minutes and longer. There was an relationship between water-holding capacity (WHC) and toughness of abalone during heating. WHC and toughness decreased during the first 10 minutes of all heating temperatures, but remained rather constant over the range of heating time at 80[degrees Celsius]. WHC increased and toughness concomitantly decreased when heating at 100[degrees Celsius] and 120[degrees Celsius] for up to 60 minutes, which were caused principally by complete gelation of collagen. Rate constant of cooking loss, degree of browning, WHC, and toughness increased with heating temperature. The activation energy of which was 6.23, 6.33, 7.09 and 13.34 kcal.mol[superscript-1],.K[superscript -1] , respectively. Heat penetration study of abalone in brine in retort pouch (150 g net weight) at 110[degrees Celsius] for 50 minutes yielded a heating rate index (f[subscript h]) of 6.7 minutes and a heating lag factor (j) 1.059. These values were further used to predict thermal process time for the product to be processed at 114[degrees Celsius] and 121[degrees Celsius] retort temperatures (RT) and 50[degrees Celsius] and 70[degrees Celsius] initial temperatures (IT). The predicted process time at IT = 50[degrees Celsius] and RT = 114[degrees Celsius] and 121[degrees Celsius] were 23 and 7 minutes, respectively, while the predicted process time at IT = 70[degrees Celsius] and RT = 114[degrees Celsius] and 121[degrees Celsius] were 22 and 6 minutes, respectively. The result from sensory evaluation of abalone processed in the above four conditions shows that the overall acceptability of the products processed at 121[degrees Celsius] were higher than those processed at 114[degrees Celsius]. During 6 months storage at room temperature, sensory score of all product attributes did not change significantly. Hazardous and spoilage bacteria were not found in all products during storage.