中国农业科学 ›› 2022, Vol. 55 ›› Issue (5): 1010-1024.doi: 10.3864/j.issn.0578-1752.2022.05.013

• 食品科学与工程 • 上一篇    下一篇

淀粉粒径对大麦淀粉物化特性的影响

肖璐婷1(),李秀红1,刘栗君1,叶发银1,2,3(),赵国华1,2,3   

  1. 1西南大学食品科学学院,重庆 400715
    2川渝共建特色食品重庆市重点实验室,重庆 400715
    3重庆市特色食品工程技术研究中心,重庆 400715
  • 收稿日期:2021-06-17 接受日期:2021-09-08 出版日期:2022-03-01 发布日期:2022-03-08
  • 通讯作者: 叶发银
  • 作者简介:肖璐婷,E-mail: xlt123456789@email.swu.edu.cn
  • 基金资助:
    国家自然科学基金面上项目(31871837);国家自然科学基金青年基金(31601401);2019年重庆市留学人员回国创业创新支持计划(cx2019071);重庆市技术创新和应用发展专项重点项目(cstc2019jscx-dxtwBX0029)

Effects of Starch Granule Size on the Physical and Chemical Properties of Barley Starches

XIAO LuTing1(),LI XiuHong1,LIU LiJun1,YE FaYin1,2,3(),ZHAO GuoHua1,2,3   

  1. 1College of Food Science, Southwest University, Chongqing 400715
    2Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, Chongqing 400715
    3Chongqing Engineering Research Center for Regional Foods, Chongqing 400715
  • Received:2021-06-17 Accepted:2021-09-08 Online:2022-03-01 Published:2022-03-08
  • Contact: FaYin YE

摘要:

【目的】大麦籽粒是一类重要的谷物原料,在啤酒酿造、禽畜喂饲、药食保健等领域的用途十分广泛。研究表明,籽粒中的淀粉颗粒大小及淀粉组成结构决定其用途。通过研究不同品种大麦不同粒径淀粉颗粒的组成结构及物化性质,为大麦淀粉加工利用提供参考。【方法】以西引2号(Xiyin-2)、京辛1号(Jingxin-1)、苏啤6号(Supi-6)3种不同用途的大麦品种籽粒为原料,采用沉降分离法得到大、中、小3个粒径的淀粉颗粒,研究颗粒显微形态、淀粉晶体结构、直链淀粉含量、支链淀粉侧链分布以及淀粉颗粒热特性、水合性质、糊化特性和消化特性与粒径的关系。【结果】大颗粒大麦淀粉多呈盘状,中颗粒淀粉呈扁圆形或椭球形,小颗粒淀粉呈球形或多角形。在偏振光显微镜下,所有大麦淀粉颗粒具有典型的偏光十字,且偏振光亮斑随粒径增加而增强。大麦淀粉的大颗粒占比最高(87.62%—89.48%),其次为中颗粒(8.97%—9.42%)和小颗粒(1.55%—3.29%)。大麦淀粉的表观直链淀粉含量为19.12—30.63 g/100 g,粒径对其含量的影响缺乏规律性。所有样品均为A型结晶,相对结晶度随着粒径增大而增加。大麦支链淀粉的侧链分布呈现双峰模式,主峰在DP 12处,次峰在DP 38处,大麦支链淀粉以B1链含量最高(34.34%—44.76%),其次是A链(25.12%—34.52%),大麦支链淀粉的平均链长为DP 22.86—25.00。热特性分析结果表明,小颗粒大麦淀粉的糊化温度区间(∆T)最大,糊化焓(∆H)则随着粒径增加而增大。大麦淀粉的膨胀力表现出品种差异,京辛1号大麦淀粉所有粒径颗粒均具有较高的膨胀力。糊化特性分析结果表明,大颗粒淀粉的峰值黏度、崩解值、终值黏度比中颗粒和小颗粒淀粉更高。消化特性分析结果表明,大麦淀粉颗粒快消化淀粉(RDS)含量随着粒径减小而增加,而粒径对其慢消化淀粉(SDS)和抗性淀粉(RS)含量的影响缺乏规律。【结论】粒径对大麦淀粉的直链淀粉含量、支链淀粉精细结构、相对结晶度等结构特征有较大影响,从而影响大麦淀粉的热特性、糊化特性及消化特性等性能。

关键词: 淀粉粒径, 大麦淀粉, 分子结构, 加工特性, 消化特性

Abstract:

【Objective】 Barley, an important source of cereal raw material, is widely used in beer brewing, livestock feeding, and medicine and food healthcare, etc. Empirical evidences have showed that the granule size, composition and structure of starch in barley grain mainly determine its use. The present research was carried out to analyze the composition, structure and physicochemical properties of starch granules with different sizes from different barley varieties, which could help enhancing the utilization of barley starch from barley processing industries. 【Method】The starch from selected barley varieties, Xiyin-2, Jingxin-1 and Supi-6, was extracted and fractionated into large, medium and small-sized fractions by using differential sedimentation methods. The effects of granular size on micromorphology, crystal structure, apparent amylose content, amylopectin side chain distribution, thermal properties, hydration properties, gelatinization properties, and digestibility properties of barley starch was investigated.【Result】 The large-sized granules were mostly discal shape, while the medium-sized granules were oblate or oval spherical shape, and the small-sized granules were spherical or polygonal shape. All barley starch granules had a typical polarized cross under a polarized light microscope, and the polarized light spots enhanced as the granule size increased. The large-sized fraction had the highest percentages (87.62%-89.48%) in barley starch, followed by medium-sized fraction (8.97%-9.42%) and small-sized fraction (1.55%-3.29%). The apparent amylose content of barley starch ranged from 19.12 to 30.63 g/100 g. The effect of granule size on its content was not regular. All the samples were A-type crystals, and the relative crystallinity augmented with the increase of granule size. The side chain distribution of barley amylopectin presented a bimodal pattern, with the main peak at DP 12 and the secondary peak at DP 38. The highest content of amylopectin in barley starch was B1 chain (34.34%-44.76%), followed by A chain (25.12%-34.52%). The average chain length of barley amylopectin was DP 22.86-25.00. The thermal characteristics of starch from barley varieties demonstrated that the gelatinization temperature range (∆T) of small-sized granules was the largest, and the gelatinization enthalpy (∆H) increased as the granule size increased. The swelling power of barley starch showed differences in varieties. All granule fractions of Jingxin-1 barley starch had higher swelling power. The results of pasting properties suggested that the small-sized granules had higher peak viscosity, breakdown and final viscosity of than the medium and small-sized granules. The results of digestibility characteristics showed that the rapidly digestible starch content of barley starch increased with the decrease of granule size, but the influence of granule size on its slowly digestible starch and resistant starch contents was not regular.【Conclusion】The granule size had a great influence on the structural characteristics of barley starch, such as the amylose content, the fine structure of amylopectin, and the relative crystallinity, thereby affecting the thermal properties, pasting properties, and digestibility characteristics of barley starch. The application characteristics of barley starch with different granule sizes were worthy of in-depth study.

Key words: starch granule size, barley starch, molecular structure, processing characteristics, digestibility characteristics