食品科学 ›› 2017, Vol. 38 ›› Issue (12): 36-42.doi: 10.7506/spkx1002-6630-201712006

• 生物工程 • 上一篇    下一篇

生物发酵处理对小米淀粉分子结构及糊化特性的影响

寇芳,康丽君,宁冬雪,夏甜天,沈?蒙,王维浩,曹龙奎   

  1. 1.黑龙江八一农垦大学食品学院,黑龙江?大庆 163319;2.国家杂粮工程技术研究中心,黑龙江 大庆 163319
  • 出版日期:2017-06-25 发布日期:2017-06-26
  • 基金资助:
    黑龙江八一农垦大学研究生创新科研项目(YJSCX2017-Y54);黑龙江省重大科技攻关项目(GA15B301)

Effects of Fermentation on Molecular Structure and Pasting Properties of Millet Starch

KOU Fang, KANG Lijun, NING Dongxue, XIA Tiantian, SHEN Meng, WANG Weihao, CAO Longkui   

  1. 1. College of Food Science, Heilongjiang Bayi Agricultural University, Daqing 163319, China; 2. National Cereals Engineering Technology Research Center, Daqing 163319, China
  • Online:2017-06-25 Published:2017-06-26

摘要: 采用0.2?g/100?mL?NaOH溶液提取发酵后的小米淀粉,研究自然发酵及优势菌(乳酸菌、酵母菌)发酵后对小米淀粉颗粒特性、结晶度、官能团、分子质量、糊化及老化特性的影响。结果如下:乳酸菌、酵母菌发酵后,淀粉颗粒表面有明显的侵蚀迹象,而自然发酵淀粉颗粒表面侵蚀迹象较轻;乳酸菌发酵后小米淀粉的结晶度较自然发酵增加1.49%而酵母菌发酵减少0.33%;发酵并未改变小米淀粉官能团区的峰位,但特征峰强度减弱,乳酸菌、酵母菌发酵后小米淀粉指纹区图谱消失;未发酵小米淀粉重均分子质量为1.5×104~5.9×105?g/mol,自然发酵分子质量在2.1×104~5.4×105?g/mol,乳酸菌发酵分子质量为1.6×104~5.3×105?g/mol,酵母菌发酵分子质量为1.6×104~4.7×105?g/mol,乳酸菌、酵母菌发酵后支链淀粉长链及直链淀粉比例减少而中间及短支链淀粉的比例相对增加;乳酸菌、酵母菌发酵96?h糊化温度较自然发酵下降0.84?℃和1.13?℃,热焓值上升1.00?J/g和0.78?J/g;二者的回生值较自然发酵分别下降743、471?mPa·s。自然发酵的优势菌(乳酸菌、酵母菌)使小米淀粉的分子结构、糊化及老化特性发生明显变化,并在小米自然发酵过程中起主导作用。

关键词: 自然发酵, 乳酸菌发酵, 酵母菌发酵, 淀粉, 分子结构, 糊化, 老化

Abstract: This study was conducted to examine the effects of natural fermentation and pure culture fermentation (with the predominant strains of lactic acid bacteria and yeast isolated from naturally fermented millet) of millet on molecular structure and pasting properties of millet starch, aiming to provide a theoretical foundation for the analysis of the effect and mechanism of pure culture fermentation on the modification of millet starch. Starches were extracted from millet fermented by different starter cultures, and they were examined for differences in granular characteristics, crystallinity, functional groups, molecular mass, and pasting and retrogradation properties. Results were obtained as follows: 1) The starch granules showed marked surface erosion after fermentation with each isolate, but were only slightly affected by natural fermentation. 2) Lactic acid bacterial fermentation yielded a 1.49% increase and a 0.33% decrease in starch crystallinity as compared to natural fermentation and yeast fermentation, respectively. 3) Fermentation did not change the peak positions in the function group region of millet starch, but decreased the characteristic peak intensity; the fingerprint region disappeared after pure culture fermentation. 4). The weight average molecular mass of unfermented millet starch was between 1.5 × 104?5.9 × 105 g/mol, that of the naturally fermented one between 2.1 × 104 ? 5.4 × 105 g/mol, and that of the lactic acid bacteria fermented one between 1.6 × 104?5.3 × 105 g/mol, and that of the yeast fermented one between 1.6 × 104?4.7 × 105 g/mol. 5) After fermentation, the proportions of long-chain amylopectin and amylose decreased, whereas the proportion of short- and middle-chain amylopectin increased. Moreover, after fermentation by the lactic acid bacteria and yeast for 96 h, the gelatinization temperature decreased 0.84 and 1.13 ℃, the enthalpy increased by 1.00 and 0.78 J/g, the setback decreased by 743 and 471 mPa·s as compared with natural fermentation, respectively. It was concluded that the dominant bacteria lactic acid bacteria and yeast in natural fermentation played a major role in changing the molecular structure, and pasting and retrogradation characteristics of millet starch.

Key words: natural fermentation, lactic acid bacteria fermentation, yeast fermentation, starch, molecular structure, gelatinization, retrogradation

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