【作者】 李培红；

【导师】 郇延军；

【作者基本信息】 江南大学 ， 农产品加工及贮藏工程， 2010， 硕士

【摘要】 传统猪肉脯的加工过程都有一个脱水烘干的操作,这将导致猪肉脯出现质地粗糙、弹性不够、切片性能差、不易成形、外表僵硬、口感较差等问题,本研究主要利用木瓜蛋白酶降解结缔组织和肌原纤维,使猪肉脯嫩化,再利用保湿剂与水的强力结合作用,在基本不改变产品水分活度的情况下,适当提高产品的水分含量,从而解决这些问题,进而提高产品的风味和口感。首先,分别研究了复合磷酸盐和木瓜蛋白酶的嫩化效果并进行对比,结果显示木瓜蛋白酶的嫩化效果更好,因此选择木瓜蛋白酶作为对猪肉脯的嫩化方法。由于木瓜蛋白酶嫩化后肌肉结构过于松散,在猪肉脯后期加工中会出现产品易碎、成型性差等问题,因此利用谷氨酰胺转氨酶来解决这一问题。双酶作用优化得到了猪肉脯质构改善效果最佳的工艺条件为：木瓜蛋白酶用量360 U/g、作用温度70℃、作用时间20 min；谷氨酰胺转氨酶用量7 U/g、作用温度50℃、作用时间2.5 h。最后利用扫描电镜观察了不同处理猪肉的超微结构,分析探讨了产品质构改善的理论依据。其次,研究了山梨醇、甘油和丙二醇这三种多羟基保湿剂对猪肉脯的保湿性能,结果显示它们对猪肉脯均具有良好的保湿效果。研究其对产品品质如嫩度、水分含量、水分活度、成品率的改善情况,发现这三种多羟基保湿剂对产品品质也都具有良好的改善作用。最后通过复配,得到这三种多羟基保湿剂对猪肉脯品质改善效果最好的工艺条件：山梨醇用量4 g/100 g、甘油用量3 ml/100g、丙二醇用量0.2 ml/100 g。最后,对品质改善后产品进行综合评价,结果发现,品质改善后的猪肉脯比起空白样品,在嫩度、成品率、水分含量等指标上都表现出了优势。将处理样品和空白样品在40℃、45℃、50℃、55℃的条件下贮藏,对比研究贮藏过程中,处理样和未处理样的贮藏特性,并建立处理样和空白样菌落总数随贮藏温度和时间变化的货架期预测模型。根据模型计算出在25℃贮藏条件下,处理样和空白样的货架期分别为212天和151天。这说明与空白样相比,处理样品的货架期得到明显提高。更多还原

【Abstract】 Dried meat slice made by traditional process is hard and difficult to chew generally.Therefor, papain is commonly used to fracture connective tissue and muscle fiber to make the dried meat slice tenderized. The humectants with many hydroxyl have the ability to combine with water. Hence the humectants are applied to improve the moisture content of the dried meat slice, without improving water activity. And flavor and taste of the products will also be improved correspondingly.First, the tenderizing effects of compound phosphate and papain were studied. The results show that papain is better to the tenderness of meat. After tenderizing by papain the muscles always show too loose, brittle, rough texture and so on. So the transglutaminase is used to cross-link the tender pork. The process conditions to improve the texture of the dried meat slice with dual-enzyme are gained as follow:the amount of papain is 360 U/g, reaction time is 20 min, reaction temperature is 70℃; the transglutaminase dosage is 7 U/g, reaction time is 2.5 h, reaction temperature is 50℃. The microstructure of pork with different treatments were observed by scanning electron microscopy to verify theoretical basis of the texture’s improvement.Second, moisture isotherms of sorbitol, glycerin and propylene glycol were studied to realize their moisturizing properties. The results reveal that all the three humectants have good moisturizing effect. The quality of products was also studied such as tenderness, moisture content, water activity, product yield. The three humectants had favorable effect to improve the quality. Through the complex test, the best compound recipe to improve the texture is obtained as follow:the amount of sorbitol 4 g/100g, glycerol 3 ml/100g and propylene glycol 0.2 ml/100g.Finally, the samples without any treatment are compared with the ones under treatment by the optimization process, the latter showed a clear advantage at all aspects of quality. The two types of samples were stored at 40℃,45℃,50℃,55℃,60℃respectively, The changes of the total number of colonies were observed and the shelf life prediction models were established. The shelf life of samples without any treatment is 151 days and the shelf life of treated samples is 212 days under the storage condition of 25℃. This indicated the shelf life of treated samples prolonged significantly comparing with untreated samples.更多还原