甜荞米中叶绿素、总酚、PPO与褐变的关系

新鲜的甜荞米呈浅绿色,储藏过程中,颜色逐渐从浅绿色变为红褐色,发生褐变,导致品质降低,商品价值降低。以新鲜甜荞米为研究对象,探讨其褐变机理。结果表明:储藏期间,色差值ΔE~*升高,其色度值ΔL~*降低,Δa~*升高,Δb~*无明显变化;甜荞米褐变是多因素多通路共同作用的结果,其中,叶绿素、酚和PPO均对甜荞米褐变有不同程度影响:叶绿素最大,酚次之,PPO最小。其中,叶绿素与色度值相关性显著,叶绿素a与ΔE~*、ΔL~*和Δa~*的相关性均大于叶绿素b;酚含量低(通荞2号)、中(赤甜1号)、高(品甜2号)3个荞麦米品种,总酚含量与色差值ΔE~*相关系数分别为:-0.568、-0.949~*和-0.962~(**),品甜2号的褐变程度最高,褐变速率最快;PPO活性随储藏时间先增加后减少。     

谷粒湿热处理对薏仁米淀粉形态、结构与热特性的影响

为了研究薏仁米除淀粉外的其他营养组分对水和热的屏障作用,对3 种薏仁米（大粒薏仁米（big Coix seed,BCS）、小粒薏仁米（small Coix seed,SCS）和半透明薏仁米（translucent Coix seed,TCS））进行湿热处理,分离提取得到薏仁米谷粒湿热处理（heat-moisture treatment,HMT）淀粉,运用扫描电子显微镜、普通光学显微镜、激光粒度仪、X射线衍射仪、傅里叶变换红外光谱仪、差示扫描量热仪等对HMT淀粉进行测定,比较处理前后淀粉的差异,探究HMT对淀粉形态、大小、结构、热特性的影响。结果表明,HMT使得淀粉颗粒表面破损、气孔增大、偏光十字减弱,淀粉双螺旋结构、结晶区和无定形区被破坏,淀粉与淀粉分子、蛋白质、脂类等的作用加强,淀粉分子有不同程度的重排。这些变化使得淀粉凝胶温度升高,晶体内异质性减弱,解螺旋所需能量下降,其中BCS淀粉的变化较小,直链淀粉含量高的TCS淀粉受HMT影响最大。因此,应依据HMT前后不同淀粉的变化在加工过程中进行合理的应用。     

银耳莲子汁饮料加工技术及配方研究

莲子、银耳是我国传统的滋补保健品。以银耳、莲子为主要原料研制的营养饮料有很好的市场前景。为了获得风味和口感良好,营养丰富及状态稳定的银耳莲子汁饮料,通过正交试验、感官评定、稳定性试验对银耳莲子汁饮料的生产工艺和产品配方进行了研究。试验结果表明:通过三因素三水平正交试验,柠檬酸0.7‰、D-异抗坏血酸钠1‰、EDTA0.6‰的护色液护色效果最好,能有效控制生产过程酶促褐变及美拉德反应;通过四因素三水平正交试验,乳化稳定剂的最佳配方为:卡拉胶0.09%、结冷胶0.02%、羧甲基纤维素钠0.07%、蔗糖酯0.08%;通过五因素四水平正交试验,银耳莲子汁的最佳配方为:莲子3%,银耳0.6%,白糖和冰糖6%,复合稳定剂0.26%,pH为6.0;按上述工艺和配方生产的银耳莲子汁饮料口感、风味最佳,稳定性良好。     

Physicochemical and structural characterisation of globulin and albumin from common buckwheat (Fagopyrum esculentum Moench) seeds

The physicochemical and conformational properties of globulin (BG) and albumin (BA) fractions from common buckwheat seeds were characterised, and compared with those of buckwheat protein isolate (BPI). The polyphenol contents were also evaluated. The polyphenol content in BA was much higher than that in BG, and most of the polyphenols in the BA was in the free form, whilst that in the BG and BPI was mainly in the protein-bound form. The BA had higher content of uncharged polar amino acids, but lower acidic amino acids than BG. The protein solubility-pH profile of the BG and BA were very different, especially at pH 4.0–6.0. Far-UV and near-UV CD and intrinsic fluorescence spectra indicated that the secondary and/or tertiary conformations of BA were much more flexible than those of BG, but also more easily affected by the polyphenols. The results indicated that the properties of BG and BA varied considerably, and were largely dependent upon their polyphenol levels and the interactions of the polyphenols and the proteins.     

In vitro gas production profiles and fermentation end‐products in processed peas,lupins and faba beans

BACKGROUND: An experiment was carried out to establish whether using a pre‐compacting device (expander) changes the contribution of dry matter (DM) and degradative behaviour of peas, lupins and faba beans over the different fractions (non‐washable fraction, NWF; insoluble washable fraction, ISWF; soluble washable fraction, SWF). Samples of the entire concentrate ingredients (WHO ingredients) and their different fractions (NWF, ISWF and SWF) were subjected to three processes (Retsch milling, R; expander treatment, E; expander‐pelleting, EP) and their fermentation characteristics were evaluated using an in vitro gas production technique. RESULTS: In peas and faba beans, both the E and EP processes increased the size of the NWF (P < 0.05) and decreased the size of the SWF compared with the R process. The maximum fractional rate of gas production in the first phase of fermentation was higher in the E and EP samples than in the R samples (P < 0.05). In lupins and faba beans the E and EP processes shifted the pattern of fermentation towards a more glucogenic fermentation, as represented by a lower non‐glucogenic to glucogenic ratio (NGR). Ammonia production (NH₃‐N) in the E and EP samples was significantly (P < 0.05) lower than that in the R samples. CONCLUSION: It is concluded that the E and EP processes provide a certain level of protection against ruminal breakdown to dietary protein and shift the pattern of fermentation towards a more glucogenic fermentation. Copyright © 2008 Society of Chemical Industry     

氦-氖激光处理蕃茄种子最适剂量的研究

激光作为育种手段已被应用了多年并且产生了许多良好的效果。但在这个领域中仍有许多具体问题有待于探索,如对某种作物或品种应用何种激光、什么剂量使其向人们预期的方向发展等等。我们以氦-氖激光为光源对蕃茄的两个品种的种子进行了不同功率密度、不同时间     

烤烟催芽包衣种子试验

为了提高包衣种子的发芽率和出苗整齐度,进行了烤烟催芽包衣种子的试验.结果表明,催芽包衣种子较常规包衣种子的发芽势提高了21.7～35.8个百分点、发芽率提高了3.2～9.2个百分点.在大理州烟区催芽包衣种子可提前出苗5～7d,苗期与大田期烟株的生长势和生长整齐度均优于常规包衣种子.     

元宝枫种壳中单宁的超声波提取及表征

利用超声波以水为溶剂提取元宝枫种壳中单宁,对超声功率、超声作用时间、水量、提取次数等因素进行研究.其较佳条件为：超声功率中挡、作用时间10～20 min,固液比为1：24,提取次效1次.波谱分析得出单宁类型为缩合型,X-衍射图表明所提单宁为非晶态化合物.     

猕猴桃果籽营养饼干的研制

以猕猴桃果籽粉、小麦粉、白砂糖、植物起酥油及磷脂为原料,研究了猕猴桃果籽营养饼干的最佳生产工艺和操作条件。结果表明:猕猴桃果籽粉20g、小麦粉200g、白砂糖60g、植物起酥油64g、磷脂12g,所得制品风味优良,色泽独特且营养丰富。