Crucian carp(Carassius auratus)is a main freshwater fish species and has been widely used as a raw material for food productions.The output of crucian carp reached 1 955 500 tons in 2009 in China,but a considerable number of them spoiled because of lacking good preservation.Therefore,it is necessary to develop an efficient method of preservation of fish.During the last decade,there has been a developing interest in edible or biodegradable films based on biopolymers,which can be used to cover the body of fish to prolong the shelf life of fish products.Fish scale is easier to obtain compared to other materials and is always abandoned.It is economical to make a kind of fishscale film obtained from fish scales by hydrolysis and the film itself can be antibacterial and antioxidant.There is a growing interest to identify antioxidative properties in many natural sources of polyphenolic compounds for food preservation,such as murta ecotypes extracts and borage extracts.Recently,as a source of antioxidant polyphenols and physiological benefits,there has been an increasing interest towards the commercial use of rosemary extracts as application for foods.The antioxidation and bacterinertness of rosemary extracts have already been verified by many reports.This paper aims to study the effects of fishscale protein hydrolysates with addition of rosemary extracts on quality changes of crucian carp during 4 ℃ storage.After being gutted and washed,the crucian carps were immersed in 4 ℃ fishscale protein hydrolysates solution and fish-scale protein hydrolysates with addition of rosemary extracts solution respectively for 1.5 min,and then packed in plastic trays after being drained.All the packed fishes were put into refrigerator maintained at 4 ℃.In order to investigate the quality changes of crucian carp during 4 ℃ storage,total bacterial counts,2-Thiobarbituric acid value,total volatile base nitrogen value,Kvalue,weight loss and sensory assessment were observed every two days.The results showed that:fishscale protein hydrolysates can significantly(P＜0.05)inhibit bacteria growth and restrain the increase of total volatile base nitrogen value,2-Thiobarbituric acid value,K value,sensory scores and weight loss for quite a long time(10 d)in contrast with the control and extent the shelf life of crucian carp during 4 ℃ storage for about 8 days; fish-scale protein hydrolysates with addition of rosemary extracts,however,can only restrain the increase of total volatile base nitrogen value,K value,weight loss and sensory scores for a short time(4-6 d)and failed to prolong the shelf life of crucian carp during 4 ℃ storage.