Effects of Pressure- and Heat-Treatment on Gel Property and Protease Activity of Meat Paste from Milkfish

• Main Authors: Guo, Jia-Chun, 郭嘉淳
• Other Authors: Ko Wen-Ching
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/78640537861285342834

碩士 === 國立中興大學 === 食品科學系 === 85 === The gel strength, whiteness, and water holding capacity of theminced milkfish gel induced by heating, heating after pressurizing,and two-step heating heating were compared. Enzymatic activity of temperature, pH, hydrostatic pressurization, and heat treatment on the protease activity were also investigated. The results obtainedwere as follows:1.The suwari of unwashed milkfish meat paste occurred at 50℃,while the modori occurred at 60℃ and 70℃. The gel strength of the washed meat paste was higher than that of unwashed. But the same tendency in thermally induced gelation was observed.2.Whiteness of milkfish gel increased with the increase of heating temperature at 30~60℃. No obvious changes were observed at 60℃ and 70℃. Water holding capacity of thermally induced gel decreased with the increase of heating temperature. Two-step heating treatment improved the gel strength and whiteness of gel, but deteriorated the water holding capacity of gel.3.High pressure treatment could improve meat paste in suwari and inhibitin modori. Gel strength. whiteness, and water holding capacity of gelobtained by heating at 30 ~ 70 ℃ could be improved by pressurizing at 3,000 atm for 30 min as pretreatment.4.The alkaline extracted from milkfish showed the maximum enzymatic activity at 60 ℃, pH 8.0 against 5% Hammarsten casein as subatrate. The alkalineprotease was activated by heating at 50 ℃ for 10 ~20 min, byt was inactivated by heating 40, 50 and 60 ℃ for 120 min. Enzymatic activity decreased with increasing pressure (~4,000 atn ) and pressurizing time (~ 30 min). The fact, alkaline protease treated at 4,000 atm for 10 min was almostcompletely inactibated, indicated that the protease was susceptible to pressure.