不同改良剂及醒发时间对马铃薯全粉面条品质特性的影响研究

采用不同改良剂和合适的醒发时间对马铃薯全粉面条品质进行改良,研究谷朊粉、海藻酸钠、食盐及不同醒发时间对面条感官品质、质构特性和蒸煮特性的影响。结果表明:加入改良剂并选取合适的醒发时间可以显著改善面条的品质,适量添加谷朊粉、氯化钠和海藻酸钠,合适的醒发时间可以提高面条的感官品质、硬度、弹性,并降低面条的蒸煮损失率。四种处理对面条感官品质影响顺序为醒发时间海藻酸钠谷朊粉食盐,对硬度的影响顺序为海藻酸钠醒发时间食盐谷朊粉,对蒸煮损失率的影响顺序为醒发时间食盐谷朊粉海藻酸钠。当醒发时间为15~60 min时,显著改善面条的感官品质、硬度、粘性及蒸煮损失率;当谷朊粉添加量为1%~3%时,显著改善面条的感官品质、硬度、内聚力、弹性和蒸煮损失率。由此可见,通过适度醒发和添加改良剂,可以显著改善马铃薯全粉面条的品质特性。     

斑点叉尾鮰鱼丸弹性的研究

通过添加魔芋精粉、马铃薯淀粉及蛋清三种辅料以提高斑点叉尾鮰鱼丸弹性及感官品质。采用单因素实验分别考察了三种辅料添加量与鱼丸弹性及感官品质的关系,再采用正交实验确定三种配料的最佳配比。结果表明:魔芋精粉2.5%、马铃薯淀粉7.5%和蛋清4.5%添加到鱼丸中,鱼丸弹性及感官综合品质最佳。     

甘薯水溶性紫色素清除DPPH自由基活性研究

从紫A4甘薯果肉及皮中分别提取水溶性紫色素,测定其黄酮含量并研究了其清除DPPH自由基的动力学性质,并与BHA、BHT比较其抗氧化能力。结果表明:紫A4甘薯皮中比果肉中含有更多的黄酮,分别为107.7mg/kg;135.6mg/kg;并且其清除DPPH自由基速度更快,而果肉提取色素抗氧化能力最强(ARP为4.76),两者抗氧化能力堪与BHA、BHT相媲美。     

不同工艺和马铃薯品种对马铃薯颗粒全粉品质的影响

本文在提出三种不同马铃薯颗粒全粉加工工艺（制片、制泥和微波工艺）的基础上，以三个主要马铃薯品种（大西洋、紫花白、克新四号）为原料，研究了不同生产工艺和马铃薯品种特性对马铃薯颗粒全粉品质的影响。研究结果表明：相同加工工艺条件下，马铃薯颗粒全粉碘蓝值和吸水力大小顺序为紫花白〉大西洋〉克新四号；相同马铃薯品种的情况下，马铃薯颗粒全粉碘蓝值大小顺序为：制片工艺制〉微波工艺〉制泥工艺，颗粒全粉吸水力大小顺序为：制片工艺〉制泥工艺〉微波工艺；马铃薯颗粒全粉的吸油力低（0．88～1．2ml/g），冻融稳定性好；加入1％（w／w）食盐或4％（w／w）的蔗糖以后，马铃薯颗粒全粉的吸水力表现出明显的下降，冻融析水力有增加的趋势；在从室温升温到95oC过程中，在温度相同的情况下，马铃薯颗粒全粉浆料的黏度，均表现出一个同样的规律即：紫花白〉大西洋〉克新四号；在95℃保温30min后的降温过程中，制片工艺加工马铃薯颗粒全粉的黏度处于不断增加的趋势，制泥工艺和微波工艺制得的马铃薯颗粒全粉的黏度基本上处于稳定状态。     

A Comparison Study of Frying Conditions on Furan Formation in 3 Potato Varieties

Furan, a typical food contaminant formed by heating process, is classified as a possible carcinogen to humans. Many factors lead to the formation of furan in food processing. In our present study, 3 potato varieties, white potato, sweet potato, and purple potato were selected to investigate the effect of thermal processing temperature and time on furan formation. The results showed that the formation of furan was highly correlated with frying temperature and time. Among the 3 potato varieties, sweet potato resulted in the highest furan concentration when fried at 200 °C for 5 min. In addition, the frying temperature and time also influenced the water activity and the color of the 3 kinds of potato slices, which had significant correlation with the formation of furan. Furan concentration decreased along with the increasing of water activity in the 3 potato varieties and the changes presented regression relationships. Meanwhile, there was an inverse correlation between furan content and color changes in the 3 potato varieties. The level of furan decreased as total color changes (ΔE) increased and the changes also presented regression relationships. These results could be used to estimate the possibility of furan formation in the 3 varieties of potato slices systems.     

The amino acid composition,solubility and emulsifying properties of sweet potato protein

A protein was purified from the high-protein type sweet potato variety 55-2 available in China. The amino acid composition, solubility and emulsifying properties of the sweet potato protein (SPP) were studied. The SPP was rich in aspartic acid (18.5%) and glutamic acid (9.30%) while essential acid amino acids made up approximately 40.7% of the SPP. The SPP was highly soluble in distilled water over a wide range of pH. However, solubility of the SPP in 1.0 M NaCl and 1.0 M CaCl₂ solutions was low especially at pH below the pI of the SPP. The SPP in CaCl₂ demonstrated emulsifying activity index (EAI) and emulsion stability index (ESI) many folds higher than those in distilled water and NaCl solution (P < 0.05).     

不同杀菌方式对泡椒鲜切马铃薯片贮藏品质的影响

为解决泡椒鲜切马铃薯片贮藏和流通过程中出现的褐变、胀袋、质地软化等问题,采用蒸汽、微波和辐照杀菌方式对泡椒鲜切马铃薯片进行处理,通过测定L*值、硬度和感官评分,筛选各杀菌方式最优工艺参数。通过贮藏实验,对比不同杀菌方式对泡椒鲜切马铃薯片色泽、质构特性、多酚氧化酶（PPO）活性及菌落总数等指标的影响。结果表明,各杀菌方式的最优工艺参数为蒸汽杀菌时间为3 min,微波杀菌功率为700 W,辐照杀菌剂量为8 kGy。贮藏实验结果表明,辐照和微波杀菌灭酶活效果优于蒸汽杀菌,但蒸汽杀菌能更好地保持产品色泽,减缓L*值的降低,维持产品硬度、弹性和咀嚼性,菌落总数和PPO活性虽比辐照处理组和微波处理组高,但整体控制在较低水平,综合感官评分以蒸汽处理组最高。综合对比,蒸汽杀菌更适合于泡椒鲜切马铃薯片的加工。     

Substituent distribution within cross-linked and hydroxypropylated sweet potato starch and potato starch

Revealing the substituents distribution within starch can help to understand the changes of starch properties after modification. The distribution of substituents over cross-linked and hydroxypropylated sweet potato starch was investigated and compared with modified potato starch. The starches were cross-linked with sodium trimetaphosphate and/or hydroxypropylated with propylene oxide. The native and modified starches were gelatinized and hydrolysed by pullulanase, β-amylase, α-amylase and a combination of pullulanase, α-amylase and amyloglucosidase. The hydrolysates were analysed by HPSEC, HPAEC and MALDI-TOF mass spectrometry. Cross-linking had only a slight effect on the enzymatic hydrolysis, where hydroxypropylation evidently limited the enzymatic hydrolysis. The results obtained suggest that the hydroxypropyl substituents are not distributed regularly over the starch chains. Although the average substitution was around 2 hydroxypropyl groups per 10 glucose units, in the enzyme digests of hydroxypropylated starches, oligomer fragments of 10–15 glucose units, carrying 5–8 hydroxypropyl groups, were identified. It is hypothesised that higher levels of substituents are present in the amorphous regions and periphery of clusters of starch granules. This is the first time that the location of hydroxypropyl groups within sweet potato starch has been examined in this detail. Despite significant differences in granule architecture between starches from potato and sweet potato, similar patterns of hydroxypropylation have been found.     

甘薯多糖的抗肿瘤研究

采用水提醇沉法从“广薯98”中提取甘薯粗多糖,通过灌胃给药,研究了甘薯多糖对荷瘤小鼠(H22)的抑瘤率、存活期和脾脏指数、胸腺指数、腹腔巨噬细胞活性的影响。其研究结果显示:甘薯多糖对H22实体瘤小鼠具有明显的抑瘤作用(P<0.05),对H22腹水瘤小鼠具有明显的延长存活期作用(P<0.05);甘薯多糖能明显增加H22实体瘤小鼠的脾脏指数、胸腺指数(P<0.05或P<0.01),能明显增强H22实体瘤小鼠的腹腔巨噬细胞活性(P<0.01)。表明甘薯多糖对H22荷瘤小鼠具有明显的抗肿瘤作用。     

紫甘薯保健醋发酵工艺优化

以紫甘薯为原料,液态发酵酿造紫甘薯保健醋,采用单因素试验、正交试验和响应面法优化酿造工艺条件。结果表明:酒精发酵最佳条件为发酵温度30℃、初始糖度16%、发酵时间72h得到酒精度最高;醋酸发酵的最佳条件为发酵温度32.01℃、初始酒精度7.25%、醋酸菌接种量9.79%、初始pH值4.54,紫甘薯醋酸度值最高,预测值为6.69%,与实际值6.73%相符。