Post-mortem changes of muscle from fresh water prawn ( Macrobrachium rosenbergii) as influenced by spawning stages

Abstract

Post-mortem changes of the muscle from pre- and post-spawned fresh water prawn ( Macrobrachium rosenbergii) were comparatively monitored during 7 days of iced storage. During the storage, the muscle of pre-spawned prawn had a greater value of trichloroacetic acid (TCA) soluble peptide, heat soluble collagen and pepsin-soluble collagen (PSC) contents than did post-spawned counterpart. Those components in the muscle of both prawns increased markedly after 3 days of storage ( p < 0.05). Conversely, insoluble collagen (ISC) content, shear force value and texture liking of both prawns decreased ( p < 0.05), indicating the softening of muscle. No changes in protein patterns were observed, except the decreased band intensity of 66 kDa protein in water soluble fraction of both prawns was found after 3 days of storage. T max and enthalpy of PSC from both prawns decreased during the first 4 days of storage ( p < 0.05), suggesting the degradation or denaturation of collagen in the muscle. Light microscopic study showed the lowering of intercellular connection of raw meat and higher gaping in cooked meat when the samples were stored for a longer time. Therefore, post-mortem characteristics of prawn muscle was affected by storage time and spawning stages.