【作者】 程译锋；

【导师】 过世东；

【作者基本信息】 江南大学 ， 动物营养与饲料科学， 2008， 硕士

【摘要】 营养性和卫生性是评价饲料质量的重要指标,加工工艺对其有重要的影响。本论文分别对鲤鱼硬颗粒饲料和膨化饲料的蛋白质体外消化率、淀粉糊化度、维生素C(晶体VC)活性保留率和有害微生物数量在加工过程中的变化进行系统研究,为鲤鱼饲料加工的营养性和安全性控制提供一定依据。物料粒度减小,能提高调质前粉状饲料的蛋白质体外消化率。调质和制粒过程中,小粒度有利于蛋白质变性和淀粉糊化,使蛋白质体外消化率和淀粉糊化度提高;增加水分有利于淀粉糊化,而对蛋白质变性、VC活性减小和有害微生物灭活的影响较小;升高温度有利于蛋白质变性和淀粉糊化,使VC活性减小和有害微生物灭活;在高温调质和制粒过程中,饲料中的绝大部分致病菌[0]可被杀灭。后熟化处理中,升高温度和延长时间,可增大淀粉的糊化度和蛋白质的变性程度,减小VC的活性。鲤鱼硬颗粒饲料的适宜加工条件为:饲料粉碎全部通过0.300 mm筛孔,在调质后水分16%～18%,温度80～90℃的条件下制粒,后熟化90～100℃,20～30 min。在此条件下,饲料的蛋白质体外消化率为82%～84%,淀粉糊化度为48%～50%,VC活性保留率为36%～40%,有害微生物灭活率接近100%。膨化饲料生产中,物料水分含量、喂料速度、螺杆转速和机筒温度的增加都使淀粉糊化度、蛋白质体外消化率和膨化度增大。机筒温度过高反而使蛋白质体外消化率减小,水分含量过高反而使膨化度减小。喂料速度、螺杆转速和机筒温度的增加都使VC活性保留率减小。水分含量的增加能缓解VC活性的损失。鲤鱼膨化饲料的适宜加工条件为:饲料粉碎全部通过0.300 mm筛孔,调质后水分26%～30%,喂料速度30～60 r/min,螺杆转速150～250 r/min,机筒温度120～135℃。在此条件下,饲料的膨化度为1.6～1.9,淀粉糊化度为90%～92%,蛋白质体外消化率为90%～92%,VC活性保留率为25%～45%。更多还原

【Abstract】 Nutrient and sanitary were important aspects in estimating feed quality, processing technology affected them significantly. The changes of in-vitro protein digestibility, starch gelatinization, L-Ascorbic acid retention and colonies of harmful microbe in carp feed during pelleting and expanding were studied in this paper.Decrease of material particle size enhanced in-vitro protein digestibility of powder feed without conditioning. During the processes of conditioning and pelleting, decrease of particle size was propitious to protein denaturizing and starch gelatinizing, thus led to higher in-vitro protein digestibility and starch gelatinization; higher moisture content was beneficial to starch gelatinizing, but had little effect on protein denaturizing, L-Ascorbic acid retention and colonies of harmful microbe; higher temperature was helpful to protein denaturizing and starch gelatinizing, and reduced colonies of harmful microbe, decreased L-Ascorbic acid retention. Most of harmful microbe could be killed in conditioning and pelleting processes with high temperature. In post-cooking, increasing temperature and time enhanced protein denaturizing and starch gelatinizing, but reduced L-Ascorbic acid retention.The befitting process conditions for carp pellet feed were as follows: material was grinded to pass screen of 0.300 mesh; moisture content was 16%～18% and temperature was 80～90℃during the processes of conditioning and pelleting; post-cooking at 90～100℃for 20～30 min. At such conditions, in-vitro protein digestibility was 82%～84%, starch gelatinization was 48%～50%, L-Ascorbic acid retention was 36%～40%, nearly 100% of harmful microbe in feed could be killed. In expanded feed processes, increases of material moisture content, feed rate, screw speed and barrel temperature enhanced starch gelatinization, in-vitro protein digestibility and expansion ratio, respectively. However, excessive temperature and excessive moisture content reduced in-vitro protein digestibility and expansion ratio, respectively. Increase of feed rate, screw speed and barrel temperature reduced L-Ascorbic acid retention. On contrary, increase of material moisture decreased the loss of L-Ascorbic acid.The befitting process conditions for carp expanded feed were as follows: material was grinded to pass screen of 0.300 mesh; moisture content was 26%～30% during conditioning precess; feed rate was 30～60 r/min; screw speed was 150～250 r/min; barrel temperature was 120～135℃. At such conditions, expansion ratio was 1.6～1.9, starch gelatinization was 90%～92%, in-vitro protein digestibility was 90%～92%, and L-Ascorbic acid retention was 25%～45%.更多还原