高粱淀粉-多酚复合物与高粱淀粉的理化性质比较分析

为探究高粱中内源性多酚对高粱淀粉理化性质的影响,分别对高粱淀粉-多酚复合物与高粱淀粉进行理化性质（溶解度、膨润力、凝沉性、冻融稳定性、黏度特性和热力学特性）研究。结果表明高粱淀粉-多酚复合物溶解度较高粱淀粉溶解度高0.37%～5.25%,而膨润力、析水率和凝沉性均低于高粱淀粉,分别下降0.14%～1.63%、1.18%和13%～27%;与高粱淀粉的糊化相比,高粱淀粉-多酚复合物峰值黏度、谷值黏度、最终黏度和回生值分别下降128 、73 、97 和24 cP,高粱淀粉-多酚复合物成糊温度较低。高粱淀粉-多酚复合物与高粱淀粉理化性质存在差异,说明高粱中内源性多酚对高粱淀粉的理化性质具有一定的影响。     

Physico-chemical Properties of Sorghum Starch Thermally Treated by Different Methods

Separate samples of sorghum were pressure cooked, extruded and popped and the physico-chemical properties of the starches compared. Pressure cooking and extrusion increased the water solubility of the samples more than did popping. Popping lead to a significant increase in beta-amylase susceptibility. Gel permeation chromatography revealed a decrease in starch molecular weight after both extrusion and popping.     

Selected Physicochemical Properties of Starch Isolated from Fermented Sorghum Flour

Starch was isolated from fermented sorghum flour (24 h natural lactic acid fermentation), and water retention, starch solubility, clarity of starch pastes and freeze‐thaw stability were measured. In comparison with starch isolated from unfermented sorghum flour, fermentation increased the solubility of the starch and decreased the water retention, but it had no effect on the freeze‐thaw stability of the starch. There was no substantial difference in the starch paste clarity between the two samples. Storage of starch pastes at lower temperature (4°C) resulted in a very low clarity of starch.     

3种高粱品种淀粉特性和酿造黄酒的风味品质分析

以‘晋杂22号’、‘晋粱白2号’、‘晋粱白3号’3 种高粱为原料酿造黄酒,分析研究淀粉对黄酒风味品质的影响。对3 种高粱进行淀粉、直链淀粉、蛋白质和脂肪质量分数等理化指标的检测;并采用扫描电子显微镜分别对3 种高粱籽粒内部胚乳结构进行分析;对3 种高粱进行淀粉提取,检测其溶解度和膨胀度;并采用差示扫描量热仪检测3 种淀粉的糊化特性;采用3 种高粱进行发酵酿造黄酒,并对3 种高粱发酵过程中的挥发性风味物质的种类和质量浓度进行检测。结果表明,3 种黄酒分别检测到102、109、110 种风味物质,总质量浓度分别为392.210、344.342、635.695 mg/L,其中异丁醇、异戊醇、苯乙醇、十六酸乙酯、9,12-十八碳二烯酸乙酯和2-甲氧基-4-乙烯基苯酚是主要的风味物质。‘晋粱白3号’的支链淀粉质量分数最高,风味物质的种类及质量浓度也最高,证明淀粉质量分数对黄酒风味物质的种类及质量浓度起到了积极影响,为黄酒酿酒原料的选择提供了理论依据。     

发芽燕麦淀粉的热特性

发芽是进一步提升谷物种子营养价值的重要手段,已经成为当前谷物研究的新热点。本文以晋燕八号燕麦为原料,通过在16℃浸泡并避光发芽,分别提取不同时间段的燕麦淀粉,用差示扫描量热(differential scanning calorimetry,DSC)和热重分析(thermogravimetric analysis,TGA)两种手段对原燕麦和发芽后燕麦淀粉的热特性进行表征。结果发现,发芽对燕麦中淀粉的起始糊化温度影响不大,在发芽144 h内,平均起始糊化温度为57.44±0.48℃,但发芽72 h以后的燕麦中淀粉糊化温度范围扩大,以发芽72 h为界,前后两段的糊化焓都是逐渐增加的,这可能提示发芽期间淀粉结构存在由无序到有序的交替变化过程;氮气氛围下,淀粉的分解温度在275~363℃之间,此温度区间内淀粉的质量损失为65%~73%;发芽淀粉热分解反应活化能比原燕麦淀粉均有降低,其中原燕麦淀粉的热分解活化能为219.44±14.46 kJ/mol,活化能最小的为发芽144 h的淀粉,其值为157.75±5.58 kJ/mol,各发芽阶段淀粉热分解反应级数均为一级。     

Thermal and Pasting Properties of Microwaved Corn Starch

Corn starch with 15–40% moisture was irradiated at 0.17 or 0.5 W/g for 1 h using the sophisticated Ethos 1600 microwave apparatus that accurately controls temperature and wattage. Temperature of irradiated starch was measured during microwaving. Thermal and pasting properties were studied on dehydrated starch after microwave irradiation. Temperature increases were greatest during the first 10 min for starch at all moisture contents at both microwave power levels. Starch irradiated at 0.17 W/g had a temperature below onset gelatinization temperature (T_o) after 1 h. Higher temperatures were observed for starch with higher moisture content and microwaved at 0.5 W/g. Compared to native starch, starch with 15–40% moisture had higher T_o (measured using differential scanning calorimetry) and with 35–40% moisture had higher peak gelatinization temperature and lower enthalpy change of gelatinization. All paste viscosity parameters measured by the Rapid Visco Analyser were reduced and pasting temperature was elevated for starch irradiated at 0.5 W/g compared to native starch.     

Thermal and Rheological Properties of Mung Bean Starch Blends with Potato,Sweet Potato,Rice, and Sorghum Starches

Blending diverse starches is green and easy to diversify starch functionalities and to lower the cost of food production. Mung bean starch is commonly used to make starch noodles with good quality. Other starches may replace the mung bean starch to reduce the production cost. Four common starches (potato, sweet potato, rice, and sorghum) were added to mung bean starch with the mixing ratio up to 100 %. The gelling, thermal, pasting, steady shear, and dynamic rheological properties of these starch systems were studied and compared. One thermal endotherm was found in all starch blends, but individual components still tended to gelatinize separately based on calculations of melting enthalpy data. However, nonlinear changes in rheological and gelling properties were mostly found, and the data can be fitted by polynomial equations (order 2), indicating the existence of interactions among components during these tests. Granule size and amylose content of starch played important roles in the nonadditive behaviors.     

高粱淀粉的研究进展

高粱是一种重要的杂粮作物,由于食用口感差,不易消化,主要用于酿酒、制糖及饲料。近年来,随着高粱品种的优化与改良,高粱的营养价值进一步改善,其应用价值也得到逐步的提高,但我国对高粱的营养和加工研究很少。淀粉是高粱的主要组分,国外对高粱淀粉的理化特性、改性以及加工利用已有较多研究,本文综述了高粱淀粉的组成特点,提取方法及其影响因素,高粱淀粉的膨胀性、凝胶性、淀粉改性等功能特性,并介绍了高粱淀粉的消化性,在食品工业中的应用以及今后的发展趋势。为指导国内高粱作物的品种选育和合理加工利用提供一定的参考。     

Structure,Physicochemical Properties,Modifications, and Uses of Sorghum Starch

Sorghum has great drought resistance and can be cultivated on marginal lands with minimal input costs. Thus, the supply of sorghum starch, the major component of the seeds, can be cheap and sustainable. This review summarizes the present knowledge of extraction, composition, granular and molecular structures, physicochemical properties, modifications, and uses of sorghum starch, and provides suggestions for needed research to improve our understanding and utilization of this starch.     

高粱自然发酵对淀粉分子结构及老化性质的影响

为明确自然发酵对高粱淀粉分子结构及老化性质的影响,将高粱进行自然发酵,利用碱提法提取高粱淀粉,研究发酵过程中淀粉颗粒表面形态、官能团、淀粉分子质量、链长分布的变化对淀粉老化性质的影响。结果表明：自然发酵后高粱淀粉颗粒表面有一定的侵蚀痕迹;发酵处理未生成新的化学基团,各官能团的峰位保持不变;发酵后淀粉的重均分子质量降低,低分子质量淀粉由74.2%增加到78.5%,同时高分子质量淀粉含量由5.4%降低至2.5%;支链淀粉的短支链百分含量降低1.8%～3.89%,长支链百分含量增加2.01%;发酵后淀粉的峰值黏度及回生值增加,其中回生值增加466?mPa·s,使发酵后的高粱淀粉更易形成凝沉,研究结果为自然发酵高粱技术调控及老化淀粉食品加工提供理论基础与数据支持。     

Properties of Korean Amaranth Starch Compared to Waxy Millet and Waxy Sorghum Starches

Characteristics of waxy type starches isolated from amaranth, waxy millet and waxy sorghum harvested in Korea were evaluated. Shapes of all starch granules were polygonal or slightly round and the surfaces of waxy millet and waxy sorghum starch granules showed visible pores. Amylose contents of the three starches were between 3.2–6.0% and amaranth starch showed the highest water binding capacity (WBC) (130.7%). The swelling power and solubility of amaranth starch studied at 65.0–95.0°C increased about 13.7‐ and 14.0‐fold, respectively, with increase in temperature. Swelling power of waxy sorghum starch was the highest (72.6 at 95°C) among the starches studied, while amaranth starch had a constant swelling power and its rate of solubility increasely only slowly at temperatures higher than 75°C. From RVA data, initial pasting temperatures of amaranth, waxy sorghum and waxy millet starches were 75.7, 73.3 and 75.2°C, respectively. Peak viscosity, breakdown, and setback from trough of amaranth starch were 68.3, 16.7 and 7.5 RVU, respectively, which were the lowest values among the starches investigated. Using DSC, onset temperature of gelatinization of amaranth starch was 1.5–4.0°C higher than those of waxy sorghum and millet starches, corresponding to the RVA result. The enthalpies of gelatinization of the starches studied in our laboratory were in the range of 8.5–12.7 J/g with decreasing order of waxy sorghum > amaranth > waxy millet starch.     

Some Effects of Starch Lipids on the Thermal and Rheological Properties of Wheat Starch

Thermal and rheological properties of starches from two different wheat varieties were examined in relation to differences in surface distribution of lipids in the starch granules. The lipids present on the outside of the granules were extracted by isopropanol and the lipids in the amylose lipid complexes were extracted by water-saturated butanol. These amylose lipid complexes influence both the thermal properties of the starch, measured by differential scanning calorimetry, and the viscosity of the starch. The starch with the greatest amount of lipids extractable by water-saturated butanol began to gelatinize at a higher temperature and the gelatinization enthalpy was lower. Furthermore the viscosity began to increase at a higher temperature and the maximum viscosity was achieved at a higher temperature for this starch.     

脱脂对糯玉米淀粉热力学特性的影响

以4个糯玉米淀粉为材料,对其进行脱脂处理,分析了其对淀粉热力学特性的影响。结果表明,脱脂使淀粉中的磷元素含量显著降低,导致淀粉的起始温度、峰值温度、终值温度、峰值指数和热焓值降低,糊化范围扩大。淀粉和脱脂淀粉糊化冷藏后发生回生,表现为脱脂增加了回生淀粉的热焓值,进而增加了淀粉的回生值和峰值指数,而起始温度、峰值温度、终值温度和糊化范围受脱脂影响较小。淀粉和脱脂淀粉的热焓值存在显著的基因型差异,淀粉的热焓值以渝糯408最低,脱脂淀粉的热焓值以郑彩糯1号最低。淀粉回生后热焓值和回生值差异较小,而脱脂淀粉回生后热焓值和回生值以YA30142最高,郑彩糯1号最低。     

Dynamic Rheological and Thermal Properties of Acetylated Sweet Potato Starch

Dynamic rheological and thermal properties of acetylated sweet potato starch (SPS) pastes (5%, w/w) were evaluated as a function of the degree of substitution (DS). The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinization (ΔH) of acetylated SPS, which were determined using differential scanning calorimetry, were lower than those of native starch, and significantly decreased with an increase in DS. Magnitudes of storage modulus (G′), loss modulus (G′′) and complex viscosity (η*) of acetylated SPS pastes were determined using a small‐deformation oscillatory rheometer. Dynamic moduli (G′, G′′ and η*) values of acetylated SPS pastes except for 0.123 DS were higher than those of native starch, and they also decreased with an increase in DS. The tan δ (ratio of G′′/G′) values (0.37–0.39) of acetylated SPS samples were lower than that (0.44) of native starch and no significant differences were found among acetylated SPS samples, indicating that the elastic properties of SPS pastes were affected by acetylation but did not depend on DS. The G′ values of acetylated SPS during aging at 4°C for 10 h were much lower than those of native starch, showing that the addition of acetyl groups produced a pronounced effect on the retrogradation properties of SPS.     

Starch Hydrolysis During Sorghum Beer Brewing

Samples were taken at different stages of sorghum beer brewing and the starch isolated. The physico-chemical properties of the starch were determined to establish what changes occurred at the molecular level of the starch during brewing. Complete hydrolysis of the starch to fermentable sugars is never the aim of mashing during sorghum beer brewing. A certain amount of starch in the beer is required to give it its characteristic viscosity and body. This residual starch was found to be much reduced in amylose content as well as in molecular size compared with the starch in the raw materials. Debranching with isoamylase followed by gel filtration chromatography indicated that the amylopectin side chains were reduced in length by approximately half.     

锥栗原淀粉及其分离组分的热力学特性

应用差示扫描量热分析仪研究了锥栗原淀粉、直链淀粉、中间成分和支链淀粉的热力学特性。4个样品在-50～350℃的程序升温过程包含冰晶融化(-10～5℃)、糊化(40～100℃)和熔融裂解(250～310℃)3个吸热过程。当水分质量分数为65%时,它们的晶体融化峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)均升至最高。对于相同的样品,当升温速率降低时,糊化温度向低温侧移动,且伴有肩状峰;糊化时升温速率越快,其凝胶体系的峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)也越高,回生度越大;同样,糊化时降温速率越慢,凝胶体系的吸热焓(ΔH)增加,回生度增大。当糊化终止温度为100℃时,4个样品凝胶体系的DSC参数值均达到最低。锥栗原淀粉、直链淀粉、中间成分和支链淀粉凝胶体系的玻璃化转变温度(Tg)分别为-6.0、-7.1、-8.6和-7.9℃。     

Physiochemical and Rheological Characterization of Sorghum Starch

Starch was isolated from the seeds of 3 sorghum cultivars and compared with commercial wheat starch. The amylose content of sorghum starches was in the range of 22.0–27.8%. Sorghum starches had less total lipids than wheat starch (1.66%) but there was no difference between sorghum Milo and Sorghum “100”. The water binding capacity of sorghum Dabar did not differ from that of wheat (100%) whereas differences in swelling power were observed, over a range of temperatures, between wheat and sorghum starches except for Sorghum “100” at 70°C. Sorghum starches showed single-step viscoamylographic curves with pronounced pasting peaks, good pasting stability and good set-back on cooling.     

Amino Acid Additives Effects on Sweet Potato Starch Thermal Properties

This study assessed the effects of amino acid additives, aspartic acid, leucine, lysine, and methionine, on the thermal characteristics of white‐fleshed and orange‐fleshed Beauregard sweet potato starches. The orange‐fleshed sweet potato (OFSPS) starch began to gelatinize at a lower temperature (56.8°C) than the white‐fleshed sweet potato starch (WFSPS) (70.1°C), but the two starches needed the same amount of energy to gelatinize. Lysine increased the gelatinization temperature of the OFSPS. The addition of leucine, aspartic acid, and methionine had no apparent impact on the OFSPS. The addition of lysine or aspartic acid increased the gelatinization temperatures of the WFSPS. Overall, the two starches used were more affected by charged amino acids than by the neutral ones.     

臭氧氧化处理对非糯性玉米淀粉热性质和回生性质的影响

以非糯性玉米淀粉为原料,采用臭氧氧化处理,获得经处理的非糯性玉米淀粉,进而采用差示扫描量热仪(differential scanning calorimeter,DSC)测定分析改性前后的玉米淀粉热性质和回生性质的变化情况。结果表明:臭氧氧化处理会改变非糯性玉米淀粉的热性质,非糯性玉米淀粉糊化温度和峰值温度随氧化时间的增长呈增大趋势,但焓变值随氧化时间的增长先增大后减小;糊化后的淀粉在4℃贮藏过程中,回生熔点和峰值温度变化的趋势与原淀粉相似,回生焓变值略高于原淀粉。因此,通过控制臭氧氧化处理可有效改变非糯性玉米淀粉热性质和回生性质。