Inhibition of Oxidant-Induced Biochemical Changes of Pork Myofibrillar Protein by Hydrolyzed Potato Protein

ABSTRACT:  The objective of the study was to investigate the role of hydrolyzed potato protein (HPP) in protecting myofibril protein isolate (MPI) from oxidative modification. MPI prepared from pork muscle was suspended (30 mg protein/mL) in 15 mM piperazine- N , N -bis(2-ethane sulfonic acid) buffer (pH 6.0) with 0, 0.3, 0.75, and 1.5 mg/mL of antioxidative HPP (1-h Alcalase hydrolysate). Oxidation was induced by incubating the protein suspensions at 4 °C for 24 h with (1) an iron-catalyzed oxidizing system (IOS: 0.01 mM FeCl₃, 0.1 mM ascorbic acid, and 1.0 mM H₂O₂) and (2) a metmyoglobin-oxidizing system (MOS: 0.1 mM metmyoglobin and 0.1 mM H₂O₂). Changes in oxidized MPI were measured as thiobarbituric acid-reactive substances (TBARS), protein carbonyl content, Ca- and K-ATPase activities, and ultraviolet (UV) spectra. Oxidation increased the production of TBARS and protein carbonyls by 2.9- and 0.24-fold in IOS and 5.6- and 2.2-fold in MOS, respectively. The 2 oxidizing systems altered the Ca- and K-ATPase activities and exposed hydrophobic groups buried in MPI. The presence of HPP reduced the extent of MPI oxidation in all physicochemical categories tested. Therefore, HPP may be used as a potential functional ingredient in meat products to enhance their oxidative stability.     

Some effects of modified-atmosphere packaging and vacuum packaging in combination with antioxidants on quality and storage life of chilled potato strips

A modified-atmosphere packaging system for chilled fresh potato strips, which rapidly produced oxygen levels < 3%, was identified. This system enclosed the strips within 25 μ low density polyethylene film heat sealed to a fibre tray lined with Surlyn-PVdC-Surlyn, and the package flushed with an initial atmosphere of 5% O₂, 10% CO₂. An equilibrium-modified atmosphere of 3–4% CO₂, 1–2% O₂ was established after 3 days' storage at 5°C. This modified-atmosphere package, used in combination with dipping of potato strips in a 10% ascorbic acid solution, inhibited enzymatic discoloration for 1 week at 5°C. Vacuum packaging within a Surlyn/PVdC-coated polyester film, with or without dipping in ascorbic acid solution, inhibited discoloration of chilled potato strips stored at 5°C for at least 2 weeks.     

马铃薯淀粉生产工艺水的再循环设计

分析宁夏南部山区淀粉生产废水资源化需求及季节性生产、高水质大用水量、低温环境等多个生产影响因素,选择以四效减压蒸发技术为核心的废水再循环流程;采用可扩充和可重用的计算机辅助设计手段,通过再循环流程主要参数及所需工艺设备的计算与选型,设计结果达到蒸汽经济性较高的目的,可为解决淀粉生产缺水和污染提供技术参考。     

淀粉烷基糖苷磺基琥珀酸酯钠盐的合成及性能研究

以甘薯淀粉烷基糖苷(APG)为原料,合成了阴离子表面活性剂淀粉烷基糖苷磺基琥珀酸酯钠盐(APGSS)。研究了影响APG与马来酸酐(MA)的酯化反应及酯与NaHSO3磺化反应的各种因素,得出比较适宜的催化剂及反应条件:酯化反应以对甲苯磺酸作催化剂,其用量为APG与马来酸酐总质量的1.5%,反应温度100℃,n(APG)∶n(MA)=1∶1,反应时间4h;磺化反应温度120℃,n(NaHSO3)∶n(酯)=1∶1,反应时间2.5 h。通过红外光谱分析确定了产物结构,并测定了产物的物理化学性能,结果表明:产物APGSS临界胶束浓度为0.2 mg/L,其泡沫性能和润湿性能比APG均有提高。     

IC反应器处理马铃薯淀粉生产废水的试验研究

试验采用超滤-IC反应器-MBR工艺处理马铃薯淀粉生产废水,重点研究了IC反应器处理马铃薯淀粉废水的工艺参数。结果表明,在常温下,当进水COD的质量浓度为6000～9000mg/L、HRT为5h、容积负荷为23.62kg[COD]/(m3·d)时,IC反应器对COD的去除率为91.43%。采用该工艺处理马铃薯淀粉生产废水完全可以达到废水回用的目的。     

甘薯淀粉性质的研究

研究了甘薯淀粉的理化性质,结果表明:其颗粒粒径的平均值为5~31mm,结晶结构属C型,直链淀粉含量18.5%,糊化温度为60.8~78.5℃。甘薯淀粉的透明度为42%,凝胶强度为98g。     

Hydroxypropyl-Distarch Phosphate from Potato Starch Increases Fecal Output, but Does Not Reduce Zinc, Iron, Calcium, and Magnesium Absorption in Rats

The physiological effects of hydroxypropyl‐distarch phosphate (HDP) were examined in rats. Male rats were fed a fiber‐free purified diet containing gelatinized potato starch (PS, 50 g/kg diet) that was not modified chemically or gelatinized, chemically modified potato starch (CMS, 50 g/kg diet) for 21 d. PS was used as the control. Six kinds of gelatinized HDP from potato with 2 different degrees of hydroxypropylation and 3 different degrees of cross‐linking were used as CMS. The wet weight and moisture of the fecal output of the rats fed highly hydroxypropylated HDP was 70% and 30% greater, respectively, than that in the control rats. The weights of the cecal wall and content of the rats fed highly hydroxypropylated HDP were 15% and 30% higher, respectively, than those of the control rats. The apparent absorption of Mg was 15% higher in the rats fed highly hydroxypropylated HDP than in the control rats. On the other hand, the apparent absorptions of Ca, Zn, and Fe were not affected by the diet. Cross‐linking did not influence the above‐mentioned physiological effects of HDP. Fecal excretion of bile acids and the plasma cholesterol concentration were not affected by the diet. These results show that the physiological effects of HDP depend on the hydroxypropylation but not the cross‐linking.     

马铃薯全粉产品品质与生产控制

马铃薯全粉产品品质与生产控制紧密相关,在生产工艺中采用回填、调质等工序处理,能更好保全马铃薯风味物质和营养成分;应用科学方法去探索和提高工艺控制及生产控制水平,是全面提高马铃薯全粉品质保障。     

新型保健食品——土豆面包的研制

研究了用土豆淀粉生产面包的较佳原料配比方案,分析了土豆淀粉对面包品质和面团品质的影响规律。结果表明,以土豆淀粉为主生产土豆面包是可行的,其生产用原料的较佳配比为:土豆淀粉60%、谷朊粉18%、小麦面粉22%。土豆淀粉的添加比例与面包的体积显著负相关;当添加比例小于50%时,随着土豆淀粉的添加比例的增大,面包的其它表观性状均有不同程度的好转。土豆淀粉的加入对面团品质影响较大:随着土豆淀粉比例的增大,评价值增大,吸水率下降,软化度先升后降。当土豆淀粉添加比例达90%时,不能形成面团。     

壳聚糖在甘薯饮料澄清中的应用

将经过一定预处理的甘薯汁用壳聚糖进行澄清处理,通过正交试验研究确定最佳澄清条件.结果表明采用壳聚糖用量0.6g/L、pH值3.0、时间2.5h、温度60℃的澄清条件效果最佳,透光率可达99%;澄清甘薯汁经调配制得风味佳且澄清透亮稳定性好的甘薯饮料.