玉米皮油提取及其理化指标的分析研究

为了开发和利用玉米皮资源,对玉米皮的营养成分以及玉米皮油的理化指标和脂肪酸组成及甘三酯组成进行了分析测定。结果表明,玉米皮粗脂肪含量为5.99%,粗蛋白质4.86%,粗纤维含量为12.45%;玉米皮油富含不饱和脂肪酸,含量高达80%以上,玉米皮油的理化指标为相对密度d2400.9135,碘值112.4 gI/100 g,皂化值189.1 mgKOH/g,不皂化物3.75%。     

玉米皮油提取及其理化指标分析

为了开发利用玉米皮资源,对玉米皮的营养成分以及玉米皮油的理化指标和脂肪酸组成及甘三酯组成进行了分析测定。结果表明,玉米皮粗脂肪含量为5.99%,粗蛋白质4.86%,粗纤维含量为12.45%;玉米皮油的相对密度0.9135,皂化值189.1mgKOH/g,碘值112.4gI/100g,不皂化物3.75%;玉米皮油脂肪酸组成中,油酸30·27%,亚油酸54·14%,棕榈酸13·68%,硬脂酸1·14%。玉米皮油富含不饱和脂肪酸,含量达80%以上。     

不同处理的精制玉米麸皮对链脲佐菌素(STZ)诱导的糖尿病小鼠的降糖作用

目的:探讨不同处理的精制玉米麸皮对链脲佐菌素(STZ)所致糖尿病小鼠高血糖的预防作用。方法:对脱淀粉、蛋白后的精制玉米麸皮分别进行酸碱处理,得到相应的酸碱降解产物。分别以精制玉米麸皮(RCB组)、精致玉米麸皮酸解产物(HAC组)、精制玉米麸皮碱解产物(HAL组)为受试物添加到小鼠饲料中喂养21d后,除正常组外,小剂量多次腹腔注射STZ建立糖尿病小鼠模型。测定各组小鼠的体质量、采食量、血糖含量、体力活力及肝脏各相关指数。结果:与对照组相比,不同处理的精制玉米麸皮可显著减少由STZ诱导的糖尿病小鼠体质量的下降程度(P<0.05),并且可显著增加小鼠体力活力,延缓疲劳的发生;酸解产物可显著抑制由STZ诱导的糖尿病小鼠血糖含量的升高(P<0.05)及显著增加肝组织中GSH和SOD的含量(P<0.05),能极显著增加肝组织中糖原的水平(P<0.01)并能显著降低肝组织中MDA的含量(P<0.05)。结论:精制玉米麸皮的酸解产物有明显预防STZ诱导的糖尿病小鼠血糖升高、体质量减轻的作用,可能与其能提高糖尿病小鼠体内抗氧化水平及保护肝糖原水平有关。     

Corn bran versus corn grain at 2 levels of forage: Intake,apparent digestibility,and production responses by lactating dairy cows

The objective of this study was to determine the effect of substituting corn bran (CB) for dried ground corn grain (CG) in the nonforage portion of high-forage (HF) and low-forage (LF) diets. Twelve multiparous and 12 primiparous Holsteins were assigned to 4 diets using six 4 ×  Latin squares with 3-wk periods. Forage was 64 or 38% of the total mixed ration (% of dry matter). On a dry matter basis, the HFCG diet had 20% CG, the LFCG diet had 39% CG, the HFCB diet had 19% CB, and the LFCB diet had 38% CB. Digestible organic matter intake (OMI) and milk energy yield were lower for CB compared with CG within forage level. Digestible OMI was greater (1.9 kg/d) for the LFCG compared with the HFCG treatment. When CB replaced forage (LFCB vs. HFCB), digestible OMI was not different but milk energy yield was greater with the LFCB diet. The LFCG diet supported the greatest milk, milk protein, and milk energy yield. Decreased concentration of milk protein and increased concentration of milk urea nitrogen when feeding CB compared with CG suggests that lack of fermentable energy in the CB diets may have limited rumen microbial protein synthesis. Total substitution of CG with CB in the nonforage portion did not support maximum milk production, even when forage was reduced at the same time (HFCG vs. LFCB). Predicted neutral detergent fiber (NDF) digestibility at 1 times maintenance, based on chemical analysis of the individual feeds, was 22 percentage units greater for CB than for the forage mix (68.9 vs. 46.9%). In vitro NDF digestibility (30 h) was 19.4 percentage units greater for CB than for the forage mix (68.9 vs. 49.5%). However, in vivo NDF digestibility of the diet when CB replaced forage (HFCB vs. LFCB) was similar (44.1 vs. 44.5%). Similarly, predicted total digestible nutrients at the production level of intake, based on chemical analysis, were greater for the CB treatments and lower for the CG treatments than those observed in vivo.     

玉米麸皮不同处理及其成分分析

为探讨玉米麸皮的生理功能,需对玉米麸皮进行处理。通过酶处理除去玉米麸皮中含量较多的蛋白质和淀粉,得到精制玉米麸皮并确定最佳酶解工艺。再分别对精制玉米麸皮进行酸碱处理,得到相应的酸碱解产物。对玉米麸皮、精制玉米麸皮、酸解产物和碱解产物基本成分组成及膳食纤维组成进行分析。结果显示碱性蛋白酶去除玉米麸皮蛋白质的作用要好于酸性蛋白酶和中性蛋白酶。蛋白酶和淀粉酶能使玉米麸皮中的蛋白质和淀粉由10.32%和17.5%分别减少到1.65%和1.23%。精制玉米麸皮总膳食纤维比玉米麸皮增加26%。酸解产物和碱解产物基本成分是可溶性膳食纤维,其中可溶性半纤维素分别为83.52%和86.82%,不含纤维素和木质素。     

Processed and prepared corn products as sources of lutein and zeaxanthin: compositional variation in the food chain

ABSTRACT:  Widely consumed by populations of all socioeconomic classes worldwide, corn is one of the few food sources of lutein and zeaxanthin. However, data on these carotenoids in processed corn and corn as eaten are lacking. Thus, the major carotenoids in the principal brands of processed corn (canned corn, corn meal, corn flour, corn flake) and in typical corn dishes (farofa, boiled corn, pamonha, curau, fried and boiled polenta) were determined. There was marked variation between processed products and between brands of the same product, but variation between lots of the same brand was small. Canned corn had the highest zeaxanthin (11.91 to 18.06 μg/g), β-cryptoxanthin (2.32 to 3.77 μg/g), and β-carotene (1.79 to 2.75 μg/g) contents. The corn flake breakfast cereal had the second highest amount of zeaxanthin (9.08 to 12.77 μg/g). Corn meal had the highest lutein (4.02 to 7.62 μg/g) level and also had good zeaxanthin content (6.13 to 11.39 μg/g), but drastic reduction of all carotenoids, especially zeaxanthin, occurred when it was toasted to farofa. Boiled corn also had lower carotenoid levels compared to the raw corn. The wide variations in carotenoid concentrations appeared to be due mainly to varietal differences in the carotenoid composition of raw materials and to losses during processing and preparation for consumption.     

玉米膳食纤维酸奶的研制

通过试验对玉米膳食纤维酸奶的配方进行优化,对产品质量作出评价。研究表明,玉米膳食纤维酸奶的最佳配方为：玉米膳食纤维添加量为6％,白砂糖添加量为8％,保加利亚乳杆菌和嗜热链球菌的接种量为3％,同时加入0．3％海藻酸钠和0．2％琼脂的复合稳定剂。     

稻米油对涂抹再制干酪品质的影响

为研究不同比例的稻米油取代黄油对涂抹再制干酪品质的影响。测定稻米油各取代比例的再制干酪的pH、硬度、可涂抹性及感官品质,并进行比较分析。结果表明,不同稻米油添加量样品pH均在正常范围,样品硬度与可涂抹性随稻米油添加量增大而减小。切达干酪味及奶香味感官评分于稻米油添加量75%时最小,不同添加量稻米油样品感官总评分无显著性差异(P0.05)。稻米油替代黄油作为涂抹再制干酪的原料油脂具有可行性。     

玉米皮膳食纤维冰淇淋的研制

介绍了膳食纤维的作用，讨论了玉米皮纤维的浸泡条件为45℃、6h，确定了其在冰淇淋中的添加量为7％，并通过正交试验确定了冰淇淋的最佳配方。     

玉米皮半纤维素提取工艺的研究

以玉米皮为原料提取碱溶笥半纤维素,是玉米麸皮综合利用的又一有效途径,提出了适合于工业化生产的提取途径。研究结果表明,Ｃａ（ＯＨ）２水溶液为最佳提取剂,其提取半纤维素的最佳工艺参数为：提取剂浓度０．２５％,物料浓度３．３％、５０℃、２ｈ。在此工艺条例上,碱溶性半纤维素提取率为９．４７％。同时对产品进行了定性分析,确定了该提取物的化学组成。     

玉米麸皮水溶性多糖除蛋白条件研究

采用TCA法、Sevag法、酶法、酶法-TCA法结合和酶法-Sevag法结合对玉米麸皮水溶性多糖进行除蛋白研究,以蛋白质脱除率和多糖损失率为指标。结果表明:酶法-TCA法结合除蛋白最佳条件为:酶解温度55℃,酶解时间1.5h,pH7.5,加酶量2%(以底物计),TCA终浓度为1%,其蛋白质脱除率为95.24%,多糖损失率为20.02%,优于其他四种方法。此方法可用于玉米麸皮水溶性多糖中蛋白质的去除。     

玉米皮活性成分提取工艺研究进展

玉米皮是玉米加工的主要副产品,含有多种活性成分。文章综述近10年来中国玉米皮中活性成分提取工艺研究进展,展望玉米皮活性成分研究方向,旨在为玉米皮的全面开发利用提供参考。     

玉米皮多糖挤出低聚化的研究

以玉米皮为原料,经超临界CO2 流体萃取,脱脂、脱杂及酶法脱除蛋白质及淀粉后获得玉米皮多糖,采用挤出技术对其进行降解处理,制取玉米皮低聚多糖,采用黏度法测定其聚合度和分子量。通过正交试验,确定最佳挤出条件为：挤出温度175℃,料水比1:1.4,玉米皮多糖粒度0.147mm,喂料速度10kg/h。按此工艺条件处理玉米皮多糖,其聚合度由894 降低至66,分子量由144828 降至10612。     

玉米种皮中蛋白质水解特性的研究

就玉米种皮的中性蛋白酶水解问题进行了研究,指出１３９８中性蛋白酶水解蛋白质的最佳条件为：温度４０℃,时间３ｙ,底物浓度０．５％,用酶量２０００ｕ／ｇ,在此条件下,玉米种皮中蛋白质可有５６％水解溶出。     

微生物促生剂发酵玉米皮生产饲料蛋白研究

以玉米皮为基本碳源,通过单因素和正交试验,以产朊假丝酵母、啤酒酵母和白地霉联合固态发酵生产蛋白饲料进行了研究。以提高真蛋白含量为主要目的,优化得到最佳的发酵条件为菌液接种量7%,固态发酵培养基料水比1:1.8（g:mL）,发酵温度31 ℃,发酵时间80 h。在此条件下,真蛋白含量可达15.6%,是发酵前的1.94倍。     

不同生物制备方法对玉米皮膳食纤维组成和功能特性的影响

采用不同α-淀粉酶和蛋白酶从玉米皮中制备了总膳食纤维(TDF)含量分别为88.0%和82.8%的两种膳食纤维(DF)--DF1和DF2,DF1的TDF、IDF和SDF分别是玉米皮的135%、134%和172%,DF2的TDF、IDF和SDF分别是玉米皮的127%、126%和106%。考察了纤维素酶和木聚糖酶对DF2的组成和功能特性的影响。经纤维素酶处理得到膳食纤维DF3,其可溶性膳食纤维(SDF)含量是DF2的4.02倍,其溶胀性(SW)和持油力(OBC)也得到了显著改善(p<0.05),但HPLC测定发现DF3对胆酸盐的体外结合能力没有得到提高。经木聚糖酶处理制得的DF4的不溶性膳食纤维(IDF)比DF2提高12%,其持水性(WHC)、SW和OBC也都得到显著提高(p<0.05),而且DF4体外对胆酸钠(C)、鹅脱氧胆酸钠(CDC)、脱氧胆酸钠(DC)和牛磺胆酸钠(TC)的束缚分别是DF2的117%、578%、316%和126%。研究发现,不同方法制备的玉米皮膳食纤维具有不同的SW、WHC、OBC和对胆酸盐的结合能力,淀粉酶、蛋白酶和木聚糖酶复合处理对这些功能特性的改进作用最大。     

精制玉米麸皮对小鼠肝损伤的预防保护作用研究

目的:研究精制玉米麸皮对由D-半乳糖胺(D-GalN)所致小鼠肝损伤的预防保护作用.方法:对实验小鼠喂以对照饲料及添加精制玉米麸皮的实验饲料.喂养期满后,腹腔注射生理盐水或D-半乳糖胺.注射后6、12、24h将小鼠麻醉、解剖,取血液、肝脏和盲肠.脏器称重,通过试剂盒分别检测各组小鼠血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)活性,肝组织中丙二醛(MDA)、谷胱甘肤(GSH)含量及超氧化物岐化酶(SOD)活性.结果:与对照组比,给予小鼠含有精制玉米麸皮的实验饲料1周后,可显著降低小鼠血清ALT、AST的活性和肝组织中MDA含量,并可显著提高肝组织中SOD的活性和GSH含量.结论:精制玉米麸皮对由D-半乳糖胺所致小鼠肝损伤具有预防保护作用.     

木聚糖酶改性玉米麸皮膳食纤维粉工艺研究

以玉米麸皮为原料制备膳食纤维粉,采用木聚糖酶对其进行改性,以提高膳食纤维品质。通过木聚糖酶法,可溶性膳食纤维得率为27.49%;其最适反应条件为:木聚糖酶添加量25.7 U/g、酶解时间1.96 h、酶解温度56.09℃、酶解pH 4.68。     

Short communication: Effect of increasing levels of corn bran on milk yield and composition

Thirty-nine lactating Holstein cows (23 multiparous and 16 primiparous) were randomly assigned to 1 of 3 dietary treatments in a crossover design. Dietary treatments differed by the proportion of corn bran [10, 17.5, and 25% dry matter (DM); designated as low, medium, and high] replacing corn silage and alfalfa. The corn bran coproduct contained 8.2% moisture and 12.9% crude protein, 30.4% neutral detergent fiber (NDF), and 45.0% nonfiber carbohydrate, 9.9% ether extract, and 0.70% P (DM basis). The low treatment consisted of 15.8% NDF from forage (fNDF) and 33.1% total NDF; the medium treatment consisted of 12.9% fNDF and 32.5% total NDF; and the high diet contained 9.9% fNDF and 31.8% total NDF. Dry matter intake was not affected by treatment. The percent milk fat decreased by 0.26% with the inclusion of corn bran from 10 to 25% of the diet DM, but total milk fat yield was not affected. In comparison, corn bran increased yield of milk protein 0.12 kg/d when bran increased from 10 to 25% of the diet DM. Total milk yield tended to increase when bran increased from 10 to 25% of the diet DM, but no differences were observed on 3.5% fat-corrected milk. Lastly, feed conversion significantly improved with increasing inclusion: 1.39, 1.39, and 1.55 ± 0.05 kg of milk/kg of DMI for low, medium, and high, respectively. Observed effects were likely due to the increase in energy intake associated with increasing levels of corn bran.