玉米蛋白粉中叶黄素和玉米黄素对小鼠巨噬细胞免疫调节活性的研究

采用体外细胞培养方法,研究小鼠腹腔巨噬细胞在LPS刺激的情况下,从玉米蛋白粉中提取的叶黄素和玉米黄素对其生成NO的影响作用.噻唑蓝（MTT）法检测淋巴细胞及巨噬细胞增殖,比色分析检测巨噬细胞吞噬中性红的能力,生物法测定肿瘤坏死因子α（TNF-α）活性,Griess法测定NO含量.结果表明：叶黄素和玉米黄素对小鼠腹腔巨噬细胞的生长有一定的促进作用,当叶黄素、玉米黄素分别为5μmol/L和2.5μmol/L时对小鼠腹腔巨噬细胞产生NO表现为抑制作用,而当叶黄素的浓度在10～40μmol/L、玉米黄素的浓度在5～30μmol/L时巨噬细胞NO的生成水平表现为能显著提高正常小鼠腹腔巨噬细胞产生NO,且呈现剂量效应关系.叶黄素在20～50μ mol/L,玉米黄素在10～40 μ mol/L的浓度范围内,能够促进巨噬细胞吞噬中性红的能力,并能诱导其分泌TNF-α.     

Thermal degradation kinetics of aqueous anthocyanins and visual color of purple corn (Zea mays L.) cob

Purple corn cob was the byproduct during the corn processing. Thermal degradation kinetics and Hunter color parameters (a, b, C, h° and ΔE) of aqueous anthocyanins from purple corn cob were studied at selected temperatures (70 °C, 80 °C and 90 °C) at pH 4.0. The results indicated that the thermal degradation of anthocyanin and Hunter color C, a and ΔE parameters followed the first-order reaction kinetics, while Hunter color h° and b parameters followed zero-order reaction kinetics. The calculated values of activation energies (Ea) were 18.3, 35.9, 37.1, 31.6, 34.9 and 30.0 kJ/mol for anthocyanins, C, a, ΔE, h° and b parameters, respectively. The higher Ea indicated that greater temperature sensitivity of visual color as compared to anthocyanins content. The degradation of anthocyanins showed positive correlation with C (R² > 0.909), a (R² > 0.860) and ΔE (R² > 0.940), while the degradation of anthocyanins showed negative correlation with h° (R² > 0.828) and b (R² > 0.735) during heating.

Industrial relevance

Purple corn cob was the byproduct during the corn processing. Purple corn cob is dark purple to almost black color due to its high content of anthocyanins, which makes this byproduct a good source of anthocyanins. In this study, the excellent linear correlation between Hunter color parameters (a, b, C, h° and ΔE) and content of anthocyanins showed that the Hunter color parameters may also be used instead of anthocyanins content during heating. The advantage of using the visual Hunter color parameters may be measured as on-line quality control parameters during thermal processing of food industry.     

The effect of moisture level on high-moisture maize (Zea mays L.) under hermetic storage conditions—in vitro studies

Under humid and warm conditions harvested grains are susceptible to molding and rapid deterioration. Therefore, they should be dried to safe moisture levels that inhibit the activity of microorganisms. Drying to these moisture levels is not economical for farmers in developing countries. Preservation of grains at intermediate moisture levels under hermetic storage conditions could be feasible and economical in warm and moist climates.

The purpose of the current study was to examine the effect of various moisture contents (m.c.) on the quality of maize grains in self-regulated modified atmospheres during hermetic storage.

Maize at 14, 16, 18, 20 and 22% m.c. was initially conditioned for 28 days in tightly wrapped plastic bags and then stored in sealed containers at 30 °C for up to 75 days. Carbon dioxide produced within the containers replaced the oxygen. As the m.c. increased the time for O₂ depletion shortened, from 600 h at 14% m.c. to 12 h at 22%. The maize at 20 and 22% m.c. exhibited the highest dry matter (DM) losses, the lowest germination rates and the highest yeast and bacteria counts. The major fermentation product in the hermetically sealed maize was ethanol (0–5 g kg⁻¹ DM), along with lower concentrations of acetic acid (0–1 g kg⁻¹ DM).

The results obtained from the in vitro experiments indicate that maize at the tested moisture levels can be stored satisfactorily under sealed conditions in which self-regulated atmospheres provide protection against microflora damage. Further large-scale trials will be needed to evaluate the economic feasibility of storing high-moisture maize.     

Nitrate and Nitrite Methods of Analysis and Levels in Raw Carrots, Processed Carrots and in Selected Vegetables and Grain Products

Methods for quantitative estimation of nitrate and nitrite were compared. Levels of these ions were measured in vegetables and grain products and effects of processing on nitrate and nitrite levels in carrots were measured. These data allow more accurate estimation of ingestion levels and suggest means to reduce exposure to these ions. High performance liquid chromatography (HPLC) had better precision and recoveries than either a classical Cd-Griess method nitrate or a Griess method for nitrite. Nitrate concentration by HPLC varied greatly within and between vegetables, ranging from 1 μmol/100g in mushrooms to 5000 μmol/100g in celery and averaging 9.7 ± 4.4 μmol/100g in grains. Nitrate levels in vegetables sold as “organic” were not different (p<0.05) from conventional vegetables. No nitrite was detected in either vegetables or grains. Nitrate was unevenly distributed in carrots with the core having the most. Storage of carrots at -18°C for 10 wk did not alter nitrate levels and no nitrite developed. Fifty-seven percent of nitrate was leached into cooking liquid when frozen carrots were boiled. Thirty-two percent of nitrate was lost during canning and 47% of the remainder was in the liquid. No nitrite developed during 10 wk of canned storage.     

非热加工技术对果蔬类胡萝卜素生物利用度的影响研究进展

类胡萝卜素是一类广泛存在于果蔬食品中的脂溶性天然色素,具有多种生理功能.通常果蔬中类胡萝卜素的生物利用度较低,不同加工方式对类胡萝素的释放和生物利用度会有不同的影响,通过科学的手段提高果蔬中类胡萝卜素的生物利用度成为果蔬加工领域研究的热点.本文简述了不同非热加工技术(高压均质技术,超高压技术,超声波技术,高压脉冲电场技...     

蛹虫草固态发酵对玉米粉加工性质及消化性的影响

利用蛹虫草固态发酵法对玉米粉性质进行改良.测定发酵前后玉米粉的理化性质,利用快速粘度分析仪和质构仪测定发酵前后玉米粉加工性质,来探究蛹虫草发酵对玉米粉性质的影响.研究结果表明,发酵0～2 d理化成分变化不显著(P>0.05),2 d后发生明显变化,至发酵第3 d,总淀粉含量降低了11.7％,直链淀粉增加了29.8％;经...     

菠萝蜜多糖对小鼠肠道菌群的调节作用

为探究菠萝蜜多糖（JFP-Ps）对小鼠肠道菌群多样性及其结构的影响,将24只雄性昆明小鼠随机分为四组:对照组、JFP-Ps（50 mg/kg BW）组、JFP-Ps（100 mg/kg BW）组和JFP-Ps（200 mg/kg BW）组,连续灌喂2周后,收集新鲜小鼠粪便,提取粪便DNA扩增肠道菌群16S rRNA基因的V3~V4区,通过Illumina高通量测序技术研究菠萝蜜多糖对小鼠肠道菌群的调节作用。结果表明,JFP-Ps可通过调节拟杆菌门（Bacteroidetes）和厚壁菌门（Firmicutes）等肠道优势菌群的组成和结构,增加肠道菌群的多样性。通过属水平分析发现,JFP-Ps可增加拟杆菌属（Bacteroides）、异杆菌属（Allobaculum）、乳酸杆菌属（Lactobacillus）和副拟杆菌（Parabacteroides）等产SCFAs菌属的丰度,减少普雷沃菌属（Prevotella）等菌属丰度,发挥肠道微生物调节作用,改善宿主肠道微生态健康,研究结果为JFP-Ps在肠道益生产品的研发应用奠定理论基础。     

Effects of Processing on Aflatoxin Levels and on Mutagenic Potential of Tortillas made from Naturally Contaminated Corn

Naturally contaminated corn containing 127 μ total aflatoxin per kg was divided into kg samples and treated with Ca(OH)2 for making tortillas. The treatments varied in % Ca(OH)2, boiling time, and holding time. Samples were taken after each processing step. Afla-toxin levels and mutagenic activity of acetone extractions of alka-line and reacidified products were measured. All treatments caused a decrease of aflatoxin (up to 46%); however, acidifying products prior to analysis caused reformation of much of the original aflatoxin. All treatments also effected a decrease in the mutagenic potential of the products, except for that of the acidified tortillas which was higher than that of the control corn. The tortilla manufacturing process may not be as effective in aflatoxin destruction as originally surmised.     

Radiation Processing of Minimally Processed Carrot (Daucus carota) and Cucumber (Cucumis sativus) to Ensure Safety: Effect on Nutritional and Sensory Quality

ABSTRACT: In the present study, radiation processing of minimally processed carrot and cucumber at a dose of 2 kGy was carried out. The effect of this treatment on different quality parameters such as vitamin C content, total carotenoids content, sensory quality, texture, and color was determined over a storage period of 16 d at 8°C to 10° C. In the case of cucumber, treatment of irradiation as well as storage period showed no significant change in the total vitamin C content of either the control or the irradiated samples. In the case of carrots, a 2-kGy dose had no significant effect ( P < 0.05) on total vitamin C content of the samples. However, during storage, both control as well as irradiated samples showed significant decrease ( P < 0.05) in vitamin C content. Total carotenoids content in carrot remained almost unchanged after irradiation as well as during storage. Sensory evaluation results showed that irradiation had no significant ( P < 0.05) effect on the ratings of any of the sensory attributes in carrot. Radiation processing of cucumber affected the flavor significantly. However, this change did not alter the overall acceptability of cucumber. Textural studies revealed that in both carrot and cucumber, there was no significant change ( P < 0.05) in firmness of the central region after irradiation, whereas the peripheral region in carrot showed significant reduction in firmness. In the case of cucumber, there was no significant change ( P < 0.05) in the texture of both peripheral regions. However, during storage, the peripheral regions of carrot and cucumber showed significant increase in firmness. Color measurement results indicated no drastic change in color coordinates of carrot samples. Thus, the nutritional as well as sensory quality of minimally processed foods did not alter significantly after gamma irradiation.     

毛水苏多糖对糖尿病小鼠肾脏的保护作用

目的:探究毛水苏多糖(polysaccharides from Stachysbaicalensis,SBP)对糖尿病小鼠肾脏的保护作用.方法:采用高糖饲料喂养结合腹腔注射链脲佐菌素(STZ)诱导建立Ⅱ型糖尿病模型,连续灌胃28 d后,考察毛水苏多糖对糖尿病小鼠的体重、空腹血糖水平、肾脏指数、肾功能指标血肌酐(Scr)...     

Radiation Processing of Minimally Processed Pineapple (Ananas comosus Merr.): Effect on Nutritional and Sensory Quality

ABSTRACT:  Radiation processing of minimally processed pineapple at a dose of 2 kGy was investigated. Effect of this treatment on different quality parameters like vitamin C content, total carotenoids content, sensory attributes, texture, and color was determined over a storage period of 12 d at 8 to 10 °C. Results showed that the irradiation treatment showed no significant effect ( P > 0.05) on total vitamin C content of pineapple samples but a significant decrease ( P ≤ 0.05) in vitamin C during storage period in both controls as well as irradiated samples was observed. However, total carotenoids were not affected by irradiation and were stable during the whole storage period as well ( P > 0.05). Sensory evaluation studies revealed that irradiation had no significant effect ( P > 0.05) on the ratings of any of the sensory attributes of pineapple samples. Taste panelists could not differentiate between control and irradiated samples. Textural studies showed no significant effect ( P > 0.05) of irradiation as well as storage period on the firmness of the central edible region of pineapple samples. Color attributes of both control and irradiated samples showed slight variation during the storage period of 12 d. However, irradiation at 2 kGy did not have a significant effect ( P > 0.05) on all color coordinates. Thus, radiation processing with 2 kGy did not affect significantly the nutritional value as well as the sensory quality of minimally processed pineapple samples.     

万寿菊叶黄素提取分离研究

本文研究了由万寿菊提取叶黄素的条件,包括皂化处理NaOH浓度,提取时间与次数对提取效率的影响,并通过薄层层析对产品进行了分析。     

Effect of Cooking on Soluble and Insoluble Oxalate Contents in Selected Pakistani Vegetables and Beans

The present study evaluated the effects of cooking on the total, soluble and insoluble oxalate contents in six different types of locally consumed vegetables and beans (spinach, carrots, beet root, white bean, red bean and soybean). The foods were cooked in water until they reached the soft consistency (12–15 min for vegetable and 2 h for beans). The raw and cooked samples were analyzed for their soluble and insoluble oxalate contents using the HPLC techniques. The total oxalate content of raw spinach, carrot, beet root, white bean, red bean and soybean, were found to be 978 ± 5, 49 ± 7, 67 ± 12, 158 ± 16, 113 ± 15, and 497 ± 22 mg/100 g of fresh weight respectively. The total oxalate contents of these foods after boiling were 477 ± 8, 16 ± 9, 52 ± 14, 47 ± 17, 72 ± 17, and 224 ± 25 mg/100 g of fresh weight respectively. The results showed that boiling significantly (P < 0.05) reduced both soluble and insoluble oxalate contents. More losses were observed in the soluble than the insoluble oxalates. The reduction in soluble oxalate in different vegetables ranged from 16 to 66% whereas in beans ranged from 40 to 77%. The data suggests that the use of boiled vegetables can be an effective strategy for reducing the dietary intake of oxalates in individuals predisposed to the development of kidney stones.     

万寿菊叶黄素的提取及分析方法研究进展

叶黄素（lutein）是自然界广泛存在的含紫罗酮环的二羟基类胡萝卜素，也是人眼视网膜黄斑色素主要组成部分。由于叶黄素可有效预防并辅助治疗老年性黄斑退化病和白内障等眼部疾病，其在生物活性物质利用领域有广泛的应用前景。万寿菊是工业上提取分离叶黄素的理想工业原料。本文综述了近年来国内外有关万寿菊叶黄素的研究工作，着重介绍叶黄素的新型提取方法及其定性定量分析方法。     

生姜多糖的提取及其对糖尿病小鼠肠道菌群的调节作用

目的:研究生姜多糖对高脂饮食（High-fat diet,HFD）和小剂量链脲佐菌素（Streptozotocin,STZ）联合诱导的2型糖尿病（Type 2 diabetes,T2D）小鼠肠道菌群的调节作用。方法:采用热水浸提乙醇沉淀的方法,从生姜中提取出多糖,通过单因素实验和正交试验优化提取条件,随后选择最佳的脱蛋白方法得到生姜多糖（Ginger polysaccharide,GP）,并通过测定GP对2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸二铵盐（2,2'-Azinobis-（3-ethylbenzthiazoline-6-sulphonate）,ABTS）自由基和羟基自由基的清除能力,评价了其体外抗氧化能力。随后,通过高脂饮食和STZ建立2型糖尿病小鼠模型,测定各组小鼠的空腹血糖（Fasting blood glucose,FBG）浓度和糖化血清蛋白（Glycated serum protein,GSP）水平,采用16S rRNA高通量测序技术分析糖尿病小鼠的肠道菌群组成。结果:GP最优提取工艺为料液比1:20 g/mL、提取温度90 ℃、提取时间1 h;采用Sevag试剂处理5次进行脱蛋白得到GP,得率为2.91%±0.25%,其中GP中总糖含量为43.44%±0.99%;当GP浓度达到4 mg/mL时,GP对ABTS＋自由基和羟基自由基的清除率分别为66.09%和65.73%;在GP的干预下,显著降低了糖尿病小鼠FBG浓度和GSP水平（P<0.05）,16S rRNA测序结果表明,GP改变了糖尿病小鼠的肠道菌群组成和相对丰度,增加了阿德勒克氏菌属（Adlercreutzia）、阿克曼菌属（Akkermansia）和乳酸杆菌属（Lactobacillus）等有益菌的相对丰度,降低了普雷沃氏菌属（Prevotella）等有害菌的相对丰度。结论:通过热水浸提法提取和Sevag脱蛋白所得生姜多糖能改变糖尿病小鼠肠道菌群的组成,该研究结果为生姜多糖预防和治疗T2D提供了理论依据。     

灵芝多糖结合有氧运动对高血脂症小鼠的降脂和抗氧化水平的影响

探究灵芝子实体多糖联合有氧运动对高脂小鼠的降脂和抗氧化水平的影响.采用水提醇沉提法提取灵芝子实体粗多糖,然后通过去蛋白、分离纯化得到灵芝多糖纯品(Ganodema lingzhi polysaccharide,GLP),经电镜扫描和傅里叶红外光谱法分析GLP的结构特征,通过高脂饲料饲喂构建高脂小鼠模型,分别设置正常喂养...     

多汁乳菇多糖对小鼠急性酒精性肝损伤的保护作用

目的:以多汁乳菇精多糖（Refined polysaccharide from Lactarius volemus Fr,RPLV）为试验材料,探究RPLV对小鼠急性酒精性肝损伤的保护作用。方法:55只小鼠随机分为空白对照组、模型组、阳性对照组、RPLV高、低剂量组（400、100 mg/kg·BW）,连续给药30 d后,断食12 h,空白组以外的其余各组按照12 mL/kg的剂量灌胃浓度为50%乙醇溶液,建立急性酒精性损伤模型。12 h后取血,采用全血细胞分析仪测定外周白细胞（White blood cell,WBC）、红细胞（Red blood cell,RBC）和血小板（Blood platelet,PLT）含量,同时取肝脏,按照试剂盒测定血液及肝脏中的丙二醛（malondialdehyde,MAD）、还原型谷胱甘肽（glutathione,GSH）、过氧化氢酶（catalase,CAT）、超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）、甘油三酯（triglyceride,TG）、谷草转氨酶（aspartate amino transferase,AST）和谷丙转氨酶（aspartate transaminase,ALT）水平,并观察小鼠的肝脏病理切片及超微结构。结果:模型组小鼠肝脏及血液中的各项生理生化指标与空白对照组差异显著（P<0.01）,RPLV高、低剂量组肝脏和血液中的SOD、CAT、GSH-Px活力和GSH含量显著上升（P<0.01或P<0.05）,RPLV高剂量组ALT、AST活力及MDA、TG含量显著下降（P<0.01或P<0.05）;病理组织切片和超微结构的观察显示,受试样品RPLV可明显改善肝脏受损情况。结论:多汁乳菇精多糖可以一定程度上改善酒精对肝脏的损伤。     

中国毛虾活性肽对免疫抑制小鼠免疫调节作用的影响

本文以毛虾为原料,采用蛋白酶酶解获得毛虾活性肽,通过建立免疫抑制小鼠模型探究了毛虾活性肽对免疫抑制小鼠的免疫调节功能。小鼠随机分为六组:正常对照组、模型组、阳性对照组以及低、中、高剂量组,其中剂量组分别灌胃0.25 g·kg^-1 BW、0.5 g·kg^-1 BW、1.0 g·kg^-1 BW毛虾活性肽。结果表明,剂量组免疫抑制小鼠体重明显增加(P<0.05),免疫器官指数中的胸腺指数显著提高(P<0.05),此外,毛虾活性肽还促进了小鼠血清中免疫球蛋白(IgA、IgG和IgM)以及细胞因子(IL-2、IL-6和TNF-α)水平的提升(P<0.05),外周血白细胞总数基本恢复至正常水平,NK细胞活性也显著增强(P<0.05)。综上,毛虾活性肽具有改善免疫抑制剂导致的免疫功能损伤,增强免疫抑制小鼠免疫调节的作用。