薏仁米淀粉的研究进展

薏仁米是传统的药食兼用杂粮作物,除了直接作药或煮粥食用外,在食品、美容以及医药保健行业均有广泛应用。淀粉是薏仁米最主要的生化组分,约占其干重的50%~70%。薏仁米副产品,尤其与之相关食品的品质与其淀粉特性密切相关。本文从薏仁米淀粉的提取工艺、淀粉结构、理化特性（包含糊化、老化、透明度、冻融稳定性、膨胀和溶解、消化特性等）以及淀粉改性等方面的研究现状进行综述,以期为薏仁米淀粉相关的高附加值产品的研发和生产提供参考。     

基于主要营养成分含量的大小颗粒薏仁米判别

以不同产地大颗粒薏仁米(BCS)和小颗粒薏仁米(SCS)粗脂肪、蛋白质、氨基酸和矿物元素含量为基础,通过方差分析研究BCS和SCS主要营养成分是否有差别,并利用主成分分析(PCA)和支持向量机(SVM)来判别BCS和SCS。结果表明,除粗脂肪、Mg、Al外,其他所研究的营养成分均为SCS高于或与BCS无统计学上显著差异;PCA所提取的特征变量基本能区分BCS和SCS,SVM所建模型的预测准确率达100%,说明薏仁米主要营养成分结合化学计量学方法来判别BCS和SCS是可行的。     

薏仁米贮藏过程中品质的变化

以贵州兴仁薏仁米作为试验材料,研究了薏仁米贮藏过程中品质的变化。结果表明,在为期1年的贮藏过程中,薏仁米的颜色、气味、主要成分及关联指标变化明显,表明薏仁米品质随贮藏时间的延长而下降。薏仁米色泽随着贮藏时间的延长,由最初的乳白色、有光泽,逐渐变暗偏黄且带有灰色;气味也由最初的甜香气,最终呈哈败味。在贮藏期间,薏仁米的蛋白质、淀粉和灰分含量的变化无显著差异,但水分含量逐渐降低(降低37.06%),脂肪含量减少明显(减少15.00%);薏仁米贮藏过程中脂肪酸值、过氧化值、电导率、丙二醛含量升高,分别增加了272.56%,416.21%,123.78%,99.91%,脂肪酶活性呈先升后降的趋势。薏仁米的脂肪氧化是其品质变化的主要原因,关联指标如肪酸值、过氧化值、丙二醛值、脂肪酶活动度和电导率的变化,均灵敏地反映其品质的下降。     

湿热预处理对酸解淀粉纳米晶制备的影响

将湿热处理（HMT）作为一种预处理手段,对HMT淀粉进行特定高温短时间的硫酸酸解并研究其对淀粉纳米晶（SNC）制备过程的影响。湿热处理（HMT）后淀粉的热稳定性、抗酸解性得到增加。对其水解率、X射线衍射特性、粒径分布特性、热特性和外观形貌特性等研究后发现：湿热处理淀粉在69 ℃时用硫酸酸解30 min即可制备SNC,产率为11.6%,相对结晶度为43%,平均粒径为300nm。制得的SNC呈不规则形状且干燥过程中发生团聚;69 ℃酸解湿热处理淀粉不仅可以提高酸解效率,还赋予SNC一定的耐热性,可以拓宽SNC的温度使用范围。     

酯化淀粉薄膜中增塑剂与淀粉分子间相互作用的研究

采用酯化淀粉以邻苯二甲酸二乙酯（DEP）为增塑剂,经流延法制备了酯化淀粉薄膜。通过扫描电子显微（SEM）、傅立叶变换红外光谱分析仪（FT-IR）、小角/广角X射线散射（SAXS/WAXS）等现代分析技术对酯化淀粉薄膜的结构及增塑剂DEP与淀粉分子间的相互作用变化进行了系统分析。结果表明,随着增塑剂DEP含量的增加,增塑剂DEP分子减弱了淀粉分子内/间相互作用力,且导致了无定形区域中淀粉分子形成部分排列更规整的微晶结构,促使淀粉分子形成有序微区,但有序微区结构尺寸Rg在37 nm~38 nm之间变化不大。通过调节酯化淀粉薄膜中增塑剂DEP含量,可控制增塑剂分子与淀粉分子间的相互作用、淀粉分子链段在薄膜中微区的有序排列程度及其规整程度,为设计抑制增塑剂迁移的酯化淀粉薄膜材料提供了基础数据。     

明日叶/薏仁米营养保健面条的研制

为了满足人们对饮食既有营养又有保健功能的要求,本文以薏仁米粉、芭蕉芋淀粉、明日叶汁和小麦粉为主要原料制备具有保健功能的营养面条。考察了薏仁米粉、芭蕉芋淀粉、明日叶汁、黄原胶和食盐不同添加比例对明日叶/薏仁米营养面条品质的影响。通过正交实验、感官评定和物性测定确定该营养面条的最佳配方为:薏仁米粉14%,芭蕉芋淀粉10%,黄原胶0.3%,食盐1.7%,小麦粉74%的混合粉,添加混合粉质量40%的明日叶汁进行和面制作面条。按最佳配方制作的面条表面光滑、富有弹性、断条率和溶出率低、口感细腻,营养丰富且具有保健功能。     

抹茶对贮藏期间薏仁米脂质氧化的影响

目的：利用天然物质抹茶延长薏仁米货架期。方法：以新鲜薏仁米为原料，经过不同剂量抹茶茶粉处理，测定贮藏期间薏仁米的水分含量、脂肪酸值、过氧化值、丙二醛含量等各项指标及菌落总数和脂质氧化关键酶的变化。结果：经不同剂量抹茶茶粉处理均会抑制薏仁米贮藏期间脂肪酸值、过氧化值、丙二醛含量以及脂肪酶和脂肪氧化酶活性的上升，减少水分的消耗及微生物的生长繁殖。抹茶对薏仁米的保藏效果存在一定程度的剂量依赖性，但添加质量分数为0.05%和0.08%的抹茶茶粉处理的保藏效果差异较小。贮藏4个月后，与自封袋组相比，添加质量分数为0.05%的抹茶茶粉处理组中薏仁米的脂肪酸值、过氧化值和丙二醛含量分别降低了31.60%，30.77%，44.83%，脂肪酶和脂肪氧化酶活性分别降低了23.05%，28.74%，且游离脂肪酸组成和含量与新鲜薏仁米更相似。结论：抹茶能有效抑制薏仁米贮藏期间脂质氧化，延长其货架期。     

辐照处理对薏仁米中脂肪酸的影响

目的 研究了辐照剂量、温度和湿度等不同条件对薏仁米中储藏过程脂肪酸变化的影响。方法 采用气相色谱(GC)对脂肪酸样品进行检测,采用面积归一化法进行定量分析。色谱柱为CP-SIL 88毛细管柱(100m×0.25μm×0.2mm),进样量为1μl,分流比为1：10,以氦(99.999%),流速为6.3mLmin-1。结果 薏仁米中共检测出13种脂肪酸成分,其中6种不饱和脂肪酸,5种饱和脂肪酸,2种反式脂肪酸,其中C16;0、C18:1-9C、C18:2-9C,12C为薏仁米中主要脂肪酸,达到脂肪酸总含量的90以上。结论 辐照处理、高湿度、高温都会加速薏仁米中不饱和脂肪酸的氧化,导致不饱和脂肪酸含量降低,产生有害的反式脂肪酸,不利于薏仁米的储藏。     

湿热处理对马铃薯淀粉-大豆肽复合物的理化和消化特性的影响

研究湿热处理(HMT)的水分条件对马铃薯淀粉与大豆肽复合物(PS-SPT)的理化和消化性质的影响。采用扫描电子显微镜和偏光显微镜研究复合物的形貌特征;利用差示扫描量热仪测定复合物的热力学特性;采用布拉班德粘度仪测定复合物的黏度特性;采用Englyst体外消化法测定复合物的体外消化性。结果表明:HMT后淀粉-大豆肽复合物偏光十字减弱,团聚现象增加。淀粉-大豆肽复合物糊化温度(To、Tp和Tc)显著升高,焓变(ΔH)显著降低,且To、Tp和Tc随HMT水分含量的增加呈逐渐升高的趋势。与物理混合样品相比,HMT后淀粉-大豆肽复合物的起糊温度升高,膨胀度、峰值黏度、热糊黏度和冷糊黏度均出现大幅下降。随着HMT水分含量的增加,淀粉的膨胀度和峰值黏度逐步降低。蒸煮后的体外消化性表明,HMT使马铃薯淀粉-大豆肽复合物的快消化淀粉含量(RDS)降低,而抗性淀粉(RS)含量升高。35%的HMT水分条件下,马铃薯淀粉-大豆肽复合物中RDS含量最低(81.53%±1.22%),RS含量最高(11.76%±0.62%)。这说明湿热处理显著改变了马铃薯淀粉-大豆肽复合物的理化和消化特性。HMT过程中直链/支链淀粉发生重组,大豆肽的物理包埋作用,以及马铃薯淀粉带负电荷基团与大豆肽侧链基团之间的相互作用均会降低淀粉的消化性。本研究为优化含慢消化淀粉和抗性淀粉的新型低GI食品的加工方法,提供理论参考。     

湿热结合壳聚糖处理前后桄榔淀粉流变特性和热力学性质比较

探讨湿热处理（Heat-Moisture Treatment，HMT）结合不同分子量的壳聚糖（Chitosan，CS）对桄榔淀粉（Arenga pinnata Starch，APS）流变性质和热力学特性的影响。动态流变分析结果表明，HMT结合CS处理提高了凝胶体系的粘弹性模量（G′和G′′），且随着CS分子量的增加，效果越明显，当添加10 ku CS时具有最高的粘弹性模量，G′为2 899 Pa，G′′为309 Pa；HMT-APS-CS凝胶体系均表现为典型的非牛顿流体，呈现出类似固体的性质；损耗因子（tanδ）均小于1，且随着CS分子量的增加而损耗因子逐渐降低，HMT-APS-CS10具有最低的损耗因子，tanδ为0.09。静态流变分析结果表明，所有凝胶体系表现出剪切稀化现象，随CS分子量降低流体指数（n）显著降低。差示量热扫描（Differential Scanning Calorimetry，DSC）结果表明HMT结合CS处理，随CS分子量的提高，显著提高了APS的峰值温度（TP）（P<0.05），从69.42 ℃提高至86.68 ℃，显著降低了APS的糊化焓值（ΔH）（P<0.05），从3.47 J/g降低至1.07 J/g。HMT结合CS处理提高了APS凝胶结构和热力学稳定性，可为桄榔淀粉及其产品的开发利用提供一定的理论依据。     

Physicochemical,crystallinity, pasting and thermal properties of heat‐moisture‐treated pinhão starch

The effect of heat‐moisture treatment (HMT) on the properties of pinhão starches under different moisture and heat conditions was investigated. The starches were adjusted to 15, 20 and 25% moisture levels and heated to 100, 110 and 120°C for 1 h. The X‐ray diffractograms, swelling power, solubility, gel hardness, pasting properties and thermal properties of the native and HMT pinhão starches were evaluated. Compared to native starch, there was an increase in the X‐ray intensity and gel hardness of HMT starches, with the exception of the 25% moisture‐treated and 120°C heat‐treated starch. HMT reduced the swelling power and solubility of the pinhão starches when compared to native starch. There was an increase in the pasting temperature, final viscosity and setback and a decrease in the peak viscosity and breakdown of HMT pinhão starches compared to native starch. HMT increases the gelatinisation temperature of native pinhão starch and reduces gelatinisation enthalpy.     

颗粒态绿豆抗性淀粉的制备及性质研究

以绿豆淀粉为原料,采用湿热处理制备颗粒态抗性淀粉,并研究其颗粒形貌、直链淀粉含量、溶胀度、黏度及结晶性质等。试验表明:淀粉经过湿热处理后,抗性淀粉含量显著提高;湿热处理淀粉仍保持完整的颗粒外观,属于颗粒态抗性淀粉,部分淀粉颗粒表面出现了裂纹和凹坑,偏光十字强度有所减弱;湿热处理淀粉的直链淀粉含量明显增加,而溶解度、膨胀度和峰值黏度下降,淀粉糊化变得困难;X-射线衍射图谱表明原淀粉和湿热处理淀粉都为"A"型结晶,且湿热处理淀粉在15.2°、17.4°、22.9°左右的衍射峰强度有所加强。     

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

Starches from normal rice (21.72% amylose), waxy rice (1.64% amylose), normal corn (25.19% amylose), waxy corn (2.06% amylose), normal potato (28.97% amylose) and waxy potato (3.92% amylose) were heat-treated at 100 °C for 16 h at a moisture content of 25%. The effect of heat-moisture treatment (HMT) on morphology, structure, and physicochemical properties of those starches was investigated. The HMT did not change the size, shape, and surface characteristics of corn and potato starch granules, while surface change/partial gelatinization was found on the granules of rice starches. The X-ray diffraction pattern of normal and waxy potato starches was shifted from B- to C-type by HMT. The crystallinity of the starch samples, except waxy potato starch decreased on HMT. The viscosity profiles changed significantly with HMT. The treated starches, except the waxy potato starch, had higher pasting temperature and lower viscosity. The differences in viscosity values before and after HMT were more pronounced in normal starches than in waxy starches, whereas changes in the pasting temperature showed the reverse (waxy > normal). Shifts of the gelatinization temperature to higher values and gelatinization enthalpy to lower values as well as biphasic endotherms were found in treated starches. HMT increased enzyme digestibility of treated starches (except waxy corn starch); i.e., rapidly and slowly digestible starches increased, but resistant starch decreased. Although there was no absolute consistency on the data obtained from the three pairs of waxy and normal starches, in most cases the effects of HMT on normal starches were more pronounced than the corresponding waxy starches.     

Hydrothermal Modifications of Tropical Tuber Starches. 1. Effect of Heat‐Moisture Treatment on the Physicochemical,Rheological and Gelatinization Characteristics

Cassava, sweet potato and arrowroot starches have been subjected to heat‐moisture treatment (HMT) under different conditions using a response surface design of the variables. A comparative study was performed on the pasting properties, swelling behaviour and the gelatinization properties of the modified starches and also on the rheological and textural properties of their pastes. X‐ray diffraction studies have shown that cassava starch exhibited a slight decrease in crystallinity, whereas sweet potato and arrowroot starches showed an increase in crystallinity after HMT at 120ºC for 14 h with 20% moisture. The swelling volume was reduced and the solubility was enhanced for all three starches after HMT, but both effects were more pronounced in the case of arrowroot starch. The decrease in paste clarity of the starch after HMT was higher in the case of cassava and sweet potato starches. Viscosity studies showed that the peak viscosity of all three starches decreased after HMT, but the paste stability increased as seen from the reduced breakdown ratio and setback viscosity. Studies on rheological properties have shown that storage and loss moduli were higher for the starches heat‐moisture treated at higher moisture and lower temperature levels than the corresponding native starches. Storage of the gel at ‐20ºC resulted in a significant increase in storage modulus for all the three starches. All the textural parameters of the gels were altered after the treatment which depended on the nature of the starch and also the treatment condition.     

Resistant starch and thermal,morphological and textural properties of heat‐moisture treated rice starches with high‐, medium‐ and low‐amylose content

This study investigated the effects of heat‐moisture treatment (HMT) on the resistant starch content and thermal, morphological, and textural properties of rice starches with high‐, medium‐ and low‐amylose content. The starches were adjusted to 15, 20 and 25% moisture levels and heated at 110°C for 1 h. The HMT increased the resistant starch content in all of the rice starches. HMT increased the onset temperature and the gelatinisation temperature range (T_finish–T_onset) and decreased the enthalpy of gelatinisation of rice starches with different amylose contents. This reduction increased with the increase in the moisture content of HMT. The morphology of rice starch granules was altered with the HMT; the granules presented more agglomerated surface. The HMT affected the textural parameters of rice starches; the high‐ and low‐amylose rice starches subjected to 15 and 20% HMT possessed higher gel hardness.     

Effect of Heat‐Moisture Treatment on Structural and Thermal Properties of Rice Starches Differing in Amylose Content

Starches from glutinous rice (1.4% amylose), Jasmine rice (15.0% amylose) and Chiang rice (20.2% amylose) were exposed to heat‐moisture treatment (HMT) at 100 °C for 16 h and at different moisture levels (18, 21, 24 and 27%). The effect of heat‐moisture treatment on structural and thermal properties of these three rice starches was investigated. The HMT did not change the size, shape and surface characteristics of rice starch granules. The A‐type crystalline pattern of rice starches remained unchanged after HMT. The relative crystallinity (RC) and the ratio of short‐range molecular order to amorphous (RSA) of heat‐moisture treated glutinous and Jasmine rice starches decreased with increasing moisture level of the treatments. In contrast, the RC of the treated Chiang rice starch remained practically unchanged. A peak of crystalline V‐amylose‐lipid complexes was clearly presented in all treated Chiang rice starches. The peak became progressively stronger with increasing moisture level of the treatment. Differential scanning calorimetry (DSC) of all treated rice starches showed a shift of the gelatinization temperature to higher values. Increasing moisture level of the treatments increased the onset gelatinization temperature (T_o) but decreased the gelatinization enthalpy (ΔH) of rice starches. A broad gelatinization temperature range (T_c‐T_o) with a biphasic endotherm was found for all treated Chiang rice starches and Jasmine rice starch after HMT₂₇ (HMT at 27% moisture level). Additionally the (T_c‐T_o) of treated Chiang rice starches increased linearly with increasing moisture level of the treatments.     

Amylopectin structure of heat–moisture treated starches

The effects of heat–moisture treatment (HMT; moisture content of 25%, at 100°C for 24 h) on starch chain distribution and unit chain distribution of amylopectin in normal rice, waxy rice, normal corn, waxy corn, normal potato, and waxy potato starches were investigated. After HMT, starch chain distribution (amylose and amylopectin responses) of waxy corn and potato starches were identical to those of untreated starches, whereas the chromatographic response of waxy rice starch showed a slight decrease, but with a slight increase in peak tailing. This result indicated that HMT had no (or very limited) effect on the degradation of amylopectins. Analysis of unit chain distribution of amylopectins revealed that waxy characteristics affected the molecular structure of amylopectin in untreated starches, i.e., the CL of normal‐type starches was greater than that of waxy‐type starches. After HMT, the CL and unit chain distribution of all starches were no different than those of untreated starches. The results implied that changes in the physico‐chemical properties of HMT starches would be due to other phenomena rather than the degradation of amylopectin molecular structure. However, the thermal degradation of amylopectin molecules of waxy starches could occur by HMT at higher treatment temperatures (120 and 140°C).     

Effect of single and dual hydrothermal treatments on the crystalline structure,thermal properties,and nutritional fractions of pea,lentil, and navy bean starches

Pea, lentil and navy bean starches were annealed at 50 °C (70% moisture) for 24 h and heat-moisture treated at 120 °C (30% moisture) for 24 h. These starches were also modified by a combination of annealing (ANN) and heat-moisture treatment (HMT). The impact of single and dual modifications (ANN–HMT and HMT–ANN) on the crystalline structure, thermal properties, and the amounts of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) were investigated. Birefringence remained unchanged on ANN but decreased on HMT. Granular swelling and amylose leaching decreased on ANN and HMT. Relative crystallinity, gelatinization enthalpy, and short-range order on the granule surface increased on ANN but decreased on HMT. Gelatinization transition temperatures increased on ANN and HMT. Gelatinization temperature range decreased and increased on ANN and HMT, respectively. ANN and HMT increased SDS and decreased RS levels in all starches. However, RDS levels increased on ANN and HMT in pea and lentil starches but decreased in navy bean starch. In gelatinized starches, ANN and HMT decreased RDS level and increased SDS and RS levels. Changes to crystalline structure, thermal properties and amounts of RDS, SDS, and RS were modified further on ANN–HMT and HMT–ANN.     

Physicochemical properties of pressure moisture treated (PMT) and heat moisture treated (HMT) starches

Physicochemical properties of pressure moisture treated (PMT, 550 MPa, 10 min) and heat moisture treated (HMT, 100 °C, 10 h) starches were investigated. Effects of PMT and HMT were different depending on starch type. PMT starches showed dramatic changes in moisture sorption isotherm, pasting properties, thermal characteristics, solubility and swelling power (at 90 °C), and in vitro digestibility. The most dramatic difference between PMT and HMT starches was amylopectin melting transition, i.e., broadening in PMT and shift to high temperature in HMT starches. Moreover, B- and C-type starches revealed the more increase in amylopectin melting enthalpy than A-type starch. Both PMT and HMT did not increase the crystallinity but reorganized the amorphous area to compact, resulting in lower rapidly digestible starch and higher slowly digestible starch than those of native starches. Consequently, PMT changed the digestibility and physicochemical properties of starches with different modes of action compared with HMT.