Muscle Prperties Of Grass Carp During Crisping Cultivation And Characterization Of Crispness

Grass carp (Ctenopharyngodon idellus) is one of the four family-fishes. After fed with broad beans, its muscle properties will change a lot, hardness and chewiness significantly increased. The muscle still keep tight and crisp after boiled, therefore it’s popular with consumers. In this experiment, growth performance, basic nutrients, protein components, texture characteristics, impedance, thermal characteristics and microstructure of carp muscle of broad bean group and formula group carp using as control during cultivation of 100 days were analysed. The crispness characterization method based on texture parameters and near-infrared spectroscopy using hardness and chewiness characterized crispness were built. Main contents and results are as follows:(1) Growth performance of grass carp during cultivation were studied. Growth indicators of grass carp increased with the increasing time.Weight gain, feed efficiency, fatness of broad bean group were 34.88%,15.96,33.24 respectively which were significantly lower than that of the formula feed group(p<0.05), while feed coefficient and survival ratio were 6.28 and 91.67% which were significantly higer than control group. Body weight and weight of two flakes of broad bean group were lower than that of formula group. Growth performance was lower by feeding broad bean.(2) Basic nutrients, protein components, amino acids and fatty acids and minerals components of muscle were studied during the feeding period of 100 days. Water content of broad bean group decreased, while crude protein, ash and free amino acid content increased with the increasing of feeding time. After Feeding for 100 days, moisture, crude protein, crude fat and had no significant difference (p>0.10), while total sugar, amino acid and soluble solids content of back muscle of broad bean group was higher than the control group (p<0.05) and soluble solids content of abdominal muscle was lower (p<0.05).On the protein components aspect, alkali-soluble protein, collagen and matrix protein content of broad bean group which were higher than the control group (p<0.05)showed an increasing trend with the feeding time and sarcoplasmic protein content was always lower than control group. After feeding for 100 days, Fiber content, alkali-soluble protein, collagen, matrix protein of back muscle were higher than that of the control group(p<0.05).Alkali-soluble protein, collagen, matrix proteins of abdominal muscle were significantly higher than with the control group (p<0.05).EAAI were 0.842 and 0.839 of the broad bean group and the control group respectively, limiting amino acid was tryptophan and rich in lysine. Content of Na、Mg、Fe、Cu、Zn of broad bean group were higer than that of fomula feed group after feeding for 100 days.(3) the method of crispness characterization based on texture parameters and change of texture properties during cultivation were studied. On the base of the study of texture parameters and sensory quality and correlations analysis, the crispness characterization method using hardness and chewiness as indicators was built, the testing condition was P/36R probe, compression speed of 10 mm/s, compression strain of 30%.Hardness, chewiness of steamed and cooked muscle of broad bean group showed a significant increasing trend in feeding period, while the formula feed group did not change significantly, and those of broad bean group was evident higer those of formula feed group(p<0.05).(4) Impedance during culitivation and microstructure and thermal properties of muscle after feeding for 100 days were studied. Impedance and its descreasing rate decreased with increasing frequency, impedance showed the most significant decline during the frequency from 2k Hz to 4k Hz. By comparing Q the relative change of impedance value of, we know that Q of broad bean group muscle was lower than that of control group. Q value of back muscle was larger than that of abdominal muscle, the abdominal muscle was larger than thatof body surface. After feeding for 100 days, Fiber membrane of broad bean grass carp became wider, sarcomere became longer and myofibril area was larger. Protein denaturation temperature of broad bean group became higher, freezing point and melting point was lower.(5) The method of crispness characterization using near infrared spectroscopy was built. The calibration model of muscle crispness characterizing by hardness and chewiness using near infrared spectroscopy technology was built on the base of testing hardness chewiness, crude protein content, collagen content, water content, crude fat content and near-infrared spectroscopy, meanwhile the calibration models of crude protein, collagen, moisture and crude fat were established.Rc of hardness and chewiness were 0.9459 and 0.8011. SEC was 0.2062 and 0.3402 respectively. Rp were 0.7469 and 0.8249 and SEP were 0.4513 and 0.2668 respectively.