儿茶素对动物血清SOD的影响

探讨了儿茶素在不同条件下对小白鼠血清SOD水平的影响。结果表明：儿茶素均具有明显升高小白鼠血清SOD的作用（极显著高于对照2号）,不同结合形式的儿茶素（游离型、脂质体型、胶束体型）经不同旋用途径（灌胃、静脉注射）对血清SOD的影响不同,脂质体、胶束体结合型儿茶素升高血清SOD的作用优于游离型（P＜0.05）,静脉注射效果优于口服（P＜0.05）。     

儿茶素和表儿茶素对动物血脂的影响

通过6组小白鼠每天灌胃或静脉注射1.5mg儿茶素[(-)catechin]或表儿茶素(Epicatechin)试验,探讨了儿茶素和表儿茶素在不同条件下对小白鼠血脂含量的影响。结果表明:无论是采用灌胃或静脉注射方法,儿茶素和表儿茶素均具有明显降低高脂血症小白鼠血清总胆固醇(TC)、甘油三酯 (TG)、低密度脂蛋白(LDL-C)和升高高密度脂蛋白(HDL-C)的作用。且静脉注射的效果明显好于灌喂(P<0.05),儿茶素的作用好于表儿茶素,但未达到显著性差异。     

复合乳杆菌对盐酸洛哌丁胺致慢传输型便秘小鼠的缓解作用

为研究复合乳杆菌（鼠李糖乳杆菌LrGG-100、长双岐杆菌BL-11、嗜酸乳杆菌LA-99和干酪乳杆菌LC-88）对慢传输型便秘小鼠的缓解作用。使用盐酸洛哌丁胺作为便秘小鼠造模药物。将雄性BALB/c小鼠随机分成健康组、便秘组、阳性组、复合乳杆菌低、高剂量组;灌胃相应内容物21 d后,处死小鼠取样,测定小鼠小肠推进率等胃肠道功能指标、血清细胞因子水平、胃肠调节肽含量以及AQP3和c-kit的转录水平。结果显示,与便秘组相比,复合乳杆菌低、高剂量组的小肠推进率显著提高61.45%（p<0.05）、1.22倍（p<0.05）,排便时间缩短21.42%（p<0.05）、29.14%（p<0.05）,排便数量增加1.50倍（p<0.05）、1.52倍（p<0.05）,排便质量增加1.13倍（p<0.05）、1.25倍（p<0.05）;高剂量组的AQP3和c-kit基因转录水平分别是便秘组的1.82倍（p<0.05）和2.00倍（p<0.05）;灌胃复合乳杆菌能够增加血清中P物质和胃动素含量,降低血清血管活性肠肽、生长抑素和内皮素-1含量。复合乳杆菌能有效缓解便秘症状,其作用可能与胃肠调节肽水平以及AQP3和c-kit的表达有关。     

酵母源金属硫蛋白对慢性汞中毒小鼠氧化损伤的修复作用

探讨具有自主知识产权的两种酵母源金属硫蛋白（metallothionein,MT）亚型（MT-1和MT-2）对慢性汞中毒小鼠氧化损伤的修复作用。实验小鼠经氯化汞染毒,连续灌胃两种酵母源MT及二巯基丙磺酸钠（dimercaptopropansulfonate sodium,DMPS）28 d后测定小鼠体质量、全血汞含量及血清超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）活力,丙二醛（malondialdehyde,MDA）含量及机体总抗氧化能力（total antioxidative capacity,T-AOC）。与正常对照组小鼠相比,模型对照组小鼠体质量显著下降（P＜0.05）,灌胃给药28 d后,两种酵母源MT亚型高剂量组小鼠体质量显著升高（P＜0.05）;各给药组小鼠血液、肝脏及肾脏汞含量显著低于模型对照组（P＜0.05）,两种酵母源MT亚型高剂量组的排汞效果显著优于DMPS组（P＜0.05）;各给药组小鼠血清中GSH-Px、SOD活力和MDA水平及总抗氧化能力接近正常对照组小鼠水平（P＞0.05）,其中酵母源MT高剂量组的作用效果最佳,且在改善机体T-AOC方面的效果优于DMPS组（P＜0.05）,酵母源MT-1亚型升高小鼠血清SOD活力和降低血清MDA含量的作用效果明显好于酵母源MT-2亚型。两种酵母源MT对慢性汞中毒小鼠具有良好的氧化损伤保护作用及排汞效果。     

桔甘片对急性酒精性肝损伤小鼠的保护作用

探讨桔甘片（Jie-Gan Tablets,JGT）对急性酒精肝损伤小鼠的保护作用。采取50%酒精一次性灌胃（i.g）的方法建立小鼠急性酒精性肝损伤模型。检测小鼠血清中谷草转氨酶（AST）、谷丙转氨酶（ALT）、甘油三酯（TG）水平,肝组织匀浆中丙二醛（MDA）的含量及谷胱甘肽过氧化酶（GSH-Px）的活性,采用H&E染色分析组织切片形态变化,评估JGT的肝保护作用。结果显示不同剂量JGT和联苯双酯预处理能够显著抑制小鼠体内两种血清转氨酶水平的升高（p<0.05）,抑制率最高达到61.81%。JGT高剂量组显著降低血清中TG水平（p<0.05）,降幅达到34.73%。与模型组相比,阳性对照组显著逆转了MDA水平上升这一现象（p<0.01）,JGT各给药组呈剂量依赖的方式降低MDA的含量（p<0.05）,且提高了抗氧化酶GSH-Px的活性（p<0.05）,其中高剂量组MDA含量降至1.74 nmol/mg,GSH-Px活力上升至828.81 U/mg pro。H&E染色结果表明,JGT预处理能够有效改善酒精诱导的肝损伤。由此可见,JGT对ALD具有一定的预防保护作用。     

TAT-SOD脂质体对UC模型大鼠的口服治疗作用

氧化应激是造成溃疡性结肠炎（UC）的重要原因之一,而超氧化物歧化酶（SOD）是调控氧化应激的基本分子。为了探究TAT-SOD脂质体对UC模型大鼠的口服治疗作用,作者利用乙醇沉淀和大孔树脂分离的方法,从基因重组毕赤酵母菌发酵液中分离纯化TAT-SOD;利用TritonX-114相分离法,去除其细菌内毒素;利用逆向蒸发法,制备TAT-SOD脂质体;利用DSS诱导构建UC模型大鼠,经灌胃给药,通过DAI评分、结肠密度、组织切片、血清SOD酶活、血清脂多糖含量,评价其治疗效果。结果表明：初步分离获得TAT-SOD,比活为11 003 U/mg;TritonX-114对内毒素的去除率为99.30%;成功制备TAT-SOD脂质体,经体外模拟消化液处理,其酶活回收率为81.80%;动物实验中,SOD给药组与模型组相比,DAI评分均显著降低（P<0.05）,且TAT-SOD脂质体组的评分最好;结肠密度和组织切片观察发现,结肠组织损伤情况均明显改善,且TAT- SOD脂质体组的改善最好;血清中SOD酶活均显著提高（P<0.05）,且TAT-SOD脂质体组的酶活最高;血清中LPS含量无显著差异。这些表明,TAT-SOD脂质体对DSS诱导UC模型大鼠有良好的口服治疗效果,有望为UC的辅助治疗提供新的选择。     

苦菜对尼古丁中毒小鼠血清乙酰胆碱含量的影响

探讨苦菜对尼古丁中毒小鼠血清乙酰胆碱含量的影响。通过观察小鼠中毒症状选择尼古丁溶液皮下注射剂量,测定灌胃后不同时间尼古丁中毒小鼠血清乙酰胆碱含量,确定取血时间,以灌胃后小鼠血清乙酰胆碱含量为指标,比较不同部位及不同处理的苦菜样品对尼古丁中毒小鼠的影响。结果显示,小鼠皮下注射尼古丁溶液较适宜的剂量为6mg/kg;尼古丁中毒小鼠灌胃苦菜汁45min时血清乙酰胆碱含量降低11%,与尼古丁组和空白组之间差异均显著(p<0.05),选择45min为灌胃后取血时间;尼古丁中毒小鼠灌胃苦菜根汁或叶汁45min时血清乙酰胆碱含量分别降低14%、17%,与尼古丁组和空白组之间差异均显著(p<0.05);尼古丁中毒小鼠灌胃干苦菜提取物或鲜苦菜提取物45min时血清乙酰胆碱含量分别降低13%、16%,与尼古丁组和空白组之间差异均显著(p<0.05)。结果表明,苦菜对尼古丁中毒小鼠出现的血清乙酰胆碱含量升高有明显的抑制作用,可减轻小鼠尼古丁急性中毒所产生的烟碱样症状,且有效成分存在于苦菜全株各部分,有效成分可用60%乙醇溶液提取。     

葛仙米藻粉对便秘大鼠肠神经递质、ICC及水通道蛋白的影响

研究葛仙米藻粉对便秘大鼠的通便作用机理。实验进行4周,随机将大鼠分为对照组、模型组、葛仙米组。对照组连续灌胃生理盐水4周;葛仙米组大鼠连续灌胃0.8 g/kg的葛仙米4周,同时从第4周起葛仙米组灌胃3 mg/kg的盐酸洛哌丁胺;模型组从第1周到第3周灌胃等量生理盐水,第4周灌胃等量盐酸洛哌丁胺。酶联免疫吸附实验法（enzyme-linked immunosorbent assays,ELISA）测定大鼠结肠组织神经递质含量,免疫组化法测定大鼠结肠水通道蛋白表达以及Cajal间质细胞（interstitial cell of Cajal,ICC）标志物c-kit含量。结果显示：（1）模型组大鼠产生首粒黑便的时间显著高于对照组和葛仙米组（p<0.01）。（2）模型组结肠组织5-羟色胺（5-hydroxytryptamine,5-HT）、P 物质（substance P,SP）含量显著低于对照组和葛仙米组（p<0.05）,血管活性肠肽（vasoacticeintestinalpolypeptide,VIP）含量显著高于对照组和葛仙米组（p<0.05）。（3）模型组结肠水通道蛋白3（aquaporm3,AQP3）水平显著低于对照组和葛仙米组,水通道蛋白4（aquaporm4,AQP4）水平显著高于对照组和葛仙米组（p<0.05）。（4）模型组结肠ICC细胞c-kit表达显著低于对照组和葛仙米组（p<0.01）。上述结果表明,葛仙米藻粉对便秘大鼠的通便作用,其机理可能与肠神经递质5-HT、SP以及VIP分泌、ICC细胞的结构与功能以及水通道蛋白表达有关。     

金针菇源维生素D2复合片剂对去卵巢骨质疏松大鼠血清生化指标、骨及脏器影响

为探讨金针菇源维生素D（2vitamin D2,pagenumber_ebook=34,pagenumber_book=24）复合片剂对去卵巢骨质疏松大鼠血清生化指标、骨及脏器影响,采用双侧卵巢切除术建立绝经后骨质疏松大鼠模型,将SD大鼠分成假手术组（Sham组）、去卵巢组（OVX组）、OVX+市售pagenumber_ebook=34,pagenumber_book=24组（OVX+pagenumber_ebook=34,pagenumber_book=24组）、OVX+金针菇源pagenumber_ebook=34,pagenumber_book=24复合片剂组（OVX+MVHP组）,连续16周隔天灌胃给药。给药结束后采集动物血清,检测血清钙、磷、碱性磷酸酶（alkaline phosphatase,AKP）、抗酒石酸酸性磷酸酶（tartrate resistant acid phosphatase,StrACP）等生化指标,取心、肝、脾、肾、子宫等计算脏器指数,采集子宫和股骨、胫骨组织标本,制备组织切片,进行苏木精-伊红染色,运用病理图像分析系统进行观察和检测。结果表明,与OVX组相比,OVX+MVHP组血清钙浓度显著升高（p<0.05）,AKP浓度显著降低（p<0.05）,而血清磷和StrACP浓度无显著差异（p>0.05）,心、肝、肾、子宫等脏器指数差异显著（p<0.05）,而脾脏无显著差异（p>0.05）;子宫管径厚度和子宫黏膜上皮厚度显著升高（p<0.05）,子宫腔径厚度显著降低（p<0.05）,股骨和胫骨骨小梁致密,小梁间距和骨髓腔变小。初步表明金针菇源pagenumber_ebook=34,pagenumber_book=24复合片剂可一定程度预防绝经后骨质疏松症的发生。     

鹿茸水提物对小鼠抗疲劳功能的影响

目的:研究鹿茸水提物对小鼠抗疲劳功能的影响。方法:144只昆明种雄性小鼠平均分成4组,即空白组(灌胃生理盐水)、高剂量组、中剂量组和低剂量组(多肽含量分别为80、40、8mg/kg·d)。灌胃30d,末次灌胃30min后测定其负重游泳时间,并测定其血乳酸(BLA)、血清尿素氮(BUN)、肝糖原(LG)、肌糖原(MG)含量及乳酸脱氢酶(LDH)活力。结果:鹿茸水提物能明显延长小鼠负重游泳时间(p<0.05,p<0.01);降低小鼠血乳酸(p<0.01)和血清尿素氮(p<0.01)的含量;提高小鼠体内肝糖原(p<0.05,p<0.01)和肌糖原(p<0.01)的储备量及运动后乳酸脱氢酶的活力(p<0.05,p<0.01)。结论:鹿茸水提物对小鼠具有明显的抗疲劳作用。     

Effect of Muscle Condition Before Freezing and Simulated Chemical Changes During Frozen Storage on the pH and Colour of Beef

The effect of rigor temperature (RT, 35 versus 10°C), increased ionic concentration (MS, 0 versus 0·2% mixed salts), oxidized lipids (OL, 0 versus 1% added oxidized fat), increased free amino acids (FAA, 0 versus 0·3% added mixture of amino acids), fat content (FC, 0 versus 15% added fat) and excluding atmospheric gases (V, 0 versus 99·9% vacuum) on pH and colour of mince stored for one month at -20°C was studied using a complete 2(6) factorial design. Adding FAA increased the meat pH measured after storage (p<0·001). Meat lightness (Hunter L* value) was increased by increased fat content (p<0·001), higher rigor temperature (p<0·001) and oxidized lipids (p<0·05). Vacuum packing tended to preserve redness (Hunter a*) whereas the higher rigor temperature decreased redness (p<0·001). Vacuum packing (p<0·05) and increased fat content (p<0·001) increased yellowness (Hunter b*). The hue angle was lowered by increased salt concentration (p<0·01), increased free amino acids (p<0·01) and using vacuum packing (p<0·001), whereas it was raised (p<0·001) by increased fat content and higher rigor temperature. Various significant two-and three-way interactions are tabulated and discussed.     

Changes in oral processing parameters of three rice varieties

Mastication and saliva addition affects the formation of a bolus, directly playing a key role in people's eating enjoyment. However, the specific changes of oral physiological parameters and bolus moisture content in the oral processing of rice have not been studied in detail. Thus, in the present study, salivary flow rate, salivary secretion, chewing frequency, and bolus moisture content during oral processing of three rice varieties (japonica rice, indica rice, and glutinous rice) were fully investigated. The differences among different rice and changes among different oral processing stages (25%, 50%, 75%, and 100%) were analyzed. Results showed that the swallowing time of glutinous rice was significantly lower than that of japonica and indica rice (p < .05). However, there was no significant difference in the chewing frequency of the three rice varieties throughout the oral processing stages (1.59–1.66 Hz, p > .05). During oral processing, the salivary flow rates for the three kinds of rice decreased significantly (p < .05), from 37.72 ± 4.32 mg/s (0%–25% stage) to 19.83 ± 5.50 mg/s (75%–100% stage). The dry basis moisture content of the bolus increased significantly (p < .05), from 1.53 ± 0.08 (0%) to 1.96 ± 0.02 (100%). In the 75%–100% stage, the amount of saliva secretion for japonica rice was highest, followed by indica rice and glutinous rice (p < .05). At the point of swallowing (100% stage), the dry basis moisture content of all three rice-bolus' was consistent (1.94–1.99, p > .05).     

刺梨、蜂胶、山楂口服液的降血脂功能研究

为研究以刺梨、蜂胶、山楂为主要原料的口服液对膳食诱导高血脂症的降血脂功效,通过喂养高脂饲料建立高血脂模型小鼠。将喂养高脂饲料的小鼠分为高脂模型组、刺梨原汁组、刺梨蜂胶组、刺梨山楂组、刺梨蜂胶山楂组共5组,各组灌胃不同的刺梨口服液28d,灌胃期间测定小鼠的体重、采食量。28d后测定小鼠血清及肝脏的总胆固醇(TotalCholesterol,TC)、甘油三酯(Triglyceride,TG)、高密度脂蛋白(High-density Lipoprotein,HDL-C)、丙二醛(Malondialdehyde,MDA)含量。研究发现刺梨口服液可有效缓解高血脂症状,灌胃刺梨蜂胶山楂口服液的小鼠血清中的总胆固醇(TC)显著性降低了23.94%(p0.05),血清甘油三酯(TG)显著降低了46.41%(p0.05),血清中的MDA含量显著性降低了73.83%(p0.05)。研究表明刺梨蜂胶山楂口服液具有良好的降血脂功效,可有效延缓脂质过氧化速率。     

Effect of tannase treatment on protein-tannin aggregation and sensory attributes of green tea infusion

Effect of tannase enzymatic treatment on protein-tannin aggregation and sensory attributes of green tea infusion was investigated. Green tea leaves were extracted with hot water at 85 °C for 20 min, the tea infusion was then treated with tannase. Results showed that both EGCG and ECG of the tea catechins were hydrolyzed by tannase into EGC and EC, respectively, accompanied by production of gallic acid. The tannase-treated tea infusion had a relatively lower binding ability with protein. Changes in the content of tea catechins, formation of tea cream, and turbidity of tea infusion with or without tannase treatment were measured after 4 weeks. Content of catechins in the tannase-modified tea remained almost unchanged, while those without tannase treated (control) decreased significantly (p < 0.05). Meanwhile, better color appearance and less tea cream formation were observed for the tannase-treated green tea, and tea cream formed for the control after storage. Results of the sensory evaluation showed that mouth feeling, taste and the overall acceptance of the tannase-treated green tea infusion were all better than those of the control.     

膳食蛋白质与大鼠脂质代谢关系的研究

通过给予SD种Ⅱ级雄性大鼠4种不同蛋白质的高脂合成饲料,研究不同来源膳食蛋白质对脂质代谢的影响及其机理探讨。结果显示,大豆蛋白组和谷豆混合蛋白组血清TC、LDL-C、(VLDL-C+LDL-C)/TC明显低于酪蛋白组(P＜0.05),而血清HDL-C、HDL-C/TC明显高于酪蛋白组(P＜0.05)。谷类蛋白组LDL-C也明显低于酪蛋白组(P＜0.05),HDL-C明显高于酪蛋白组(P＜.05)。谷类蛋白与大豆蛋白混合后,其生物利用率提高,调节血脂的作用增强。提示大豆蛋白尤其谷豆混合蛋白有预防AS形成作用。     

桔梗醇提物对链尿菌素致糖尿病ICR小鼠血糖影响研究

目的:研究桔梗醇提物对链脲菌素致糖尿病ICR小鼠的血糖影响作用。方法:采用STZ尾静脉注射得到糖尿病模型小鼠,分别以含生药量8、4g/kg·bw醇提物、格林苯脲或纯净水进行28d灌胃实验,观察小鼠空腹血糖、血清胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白含量,以及体重、采食量、采水量变化。结果:长期服用PGE能缓解糖尿病ICR小鼠体重下降和多饮多食症状,高、低剂量PGE组血糖水平分别升高11.42%、6.86%,与模型对照组比较明显抑制了血糖的急剧升高;高、低剂量PVE均能显著地降低糖尿病小鼠血清TG、TC、LDL-C含量并提高HDL-C含量,同时对胰岛素的分泌也有一定的改善作用。     

波纹巴非蛤糖胺聚糖抗氧化作用的研究

目的:研究波纹巴非蛤糖胺聚糖体外清除自由基作用及对衰老模型小鼠的体内抗氧化作用。方法:采用体外实验研究波纹巴非蛤糖胺聚糖对羟自由基、超氧阴离子自由基、DPPH·的清除作用。体内实验采用小鼠腹腔注射D-半乳糖建立衰老模型,同时给药组灌服高、中、低3个剂量的波纹巴非蛤糖胺聚糖溶液,4周后检测各组小鼠超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)含量。结果:波纹巴非蛤糖胺聚糖精制品(PUG-1)体外对羟自由基、超氧阴离子自由基、DPPH自由基均具有较好的清除作用,IC50分别为:4.23、3.19、4.36mg/mL。与衰老模型组小鼠比较,200、400mg/kg·dPUG-1可以极显著提高衰老小鼠血清、肝脏、脑组织中SOD、GSH-Px和CAT含量(p<0.01),降低MDA含量(p<0.05)。结论:波纹巴非蛤糖胺聚糖具有体外清除自由基作用,其体内抗衰老作用可能与提高机体抗氧化酶活性有关。     

Effects of strain of Holstein-Friesian and concentrate supplementation on the fatty acid composition of milk fat of dairy cows grazing pasture in early lactation

The effect of a grain-based concentrate supplement on fatty acid (FA) intake and concentration of milk FA in early lactation was investigated in grazing dairy cows that differed in their country of origin and in their estimated breeding value for milk yield. It was hypothesized that Holstein-Friesian cows of North American (NA) origin would produce milk lower in milk fat than those of New Zealand (NZ) origin, and that the difference would be associated with lower de novo synthesis of FA. In comparison, increasing the intake of concentrates should have the same effect on the FA composition of the milk from both strains. Fifty-four cows were randomly assigned in a factorial arrangement to treatments including 3 amounts of concentrate daily [0, 3, and 6 kg of dry matter (DM)/cow] and the 2 strains. The barley/steam-flaked corn concentrate contained 3.5% DM FA, with C18:2, C16:0, and C18:1 contributing 48, 18, and 16% of the total FA. The pasture consumed by the cows contained 4.6% DM FA with C18:3, C16:0, and C18:1 contributing 51, 10, and 10% of the FA, respectively. Pasture DM intake decreased linearly with supplementation, but total DM intake was not different between concentrate or strain treatments, averaging 16.2 kg of DM/cow, with cows consuming 720 g of total FA/d. Cows of the NA strain had lesser concentrations of milk fat compared with NZ cows (3.58 vs. 3.95%). Milk fat from the NA cows had lesser concentrations of C6:0, C8:0, C10:0, C12:0, C14:0, and C16:0, and greater concentrations of cis-9 C18:1, C18:2, and cis-9, trans-11 C18:2, than NZ cows. These changes indicated that in milk from NA cows had a lesser concentration of de novo synthesized FA and a greater concentration of FA of dietary origin. Milk fat concentration was not affected by concentrate supplementation. Increasing concentrate intake resulted in linear increases in the concentrations of C10:0, C12:0, C14:0, and C18:2 FA in milk fat, and a linear decrease in the concentration of C4:0 FA. The combination of NA cows fed pasture alone resulted in a FA composition of milk that was potentially most beneficial from a human health perspective; however, this would need to be balanced against other aspects of the productivity of these animals.     

玉米肽-香菇多糖螯合物对小鼠免疫功能的影响

研究玉米肽-香菇多糖螯合物(CPG)对小鼠免疫功能的影响。实验采用玉米肽为原料通过螯合香菇多糖制备具有免疫功能的玉米肽香菇多糖螯合物(CPG),研究玉米肽(CP)、香菇多糖(G)进行对比;玉米肽低、中、高剂量组(CP-L、CP-M、CP-H);玉米肽-香菇多糖低、中、高剂量组(CPG-L、CPG-M、CPG-H);香菇多糖低、中、高剂量组(G-L、G-M、G-H),对小鼠生长性能、体液免疫能力、细胞免疫能力等方面的功能活性。结果表明:CP、CPG、G均能提高小鼠的体重,CP-M、CP-H,CPG-L、CPG-M、CPG-H,G-H剂量组均能显著(P0.05)提高免疫器官指数,且CPG组较CP组的效果更加明显;CPG对小鼠巨噬细胞增殖能力和吞噬能力的提高效果优于CP,CP-H和CPG-L、CPG-M、CPG-H剂量组能显著(P0.05)提高机体免疫球蛋白IgA水平,CP-M、CP-H和CPG-L、CPG-M、CPG-H、G-H均能显著(P0.05)提高机体免疫球蛋白IgG;CPG较CP和G更能促进细胞从G1期向S期转化,有利于提高小鼠脾淋巴细胞增殖分化能力。这表明较玉米肽和香菇多糖而言,玉米肽-香菇多糖螯合物(CPG)可以通过促进小鼠机体生长性能、体液免疫能力水平、细胞免疫能力水平更好地发挥其免疫生物学活性,是一种潜在的免疫增强剂。     

Effect of temperature of CO2 injection on the pH and freezing point of milks and creams

The objectives of this study were to measure the impact of CO2 injection temperature (0 degree C and 40 degrees C) on the pH and freezing point (FP) of (a) milks with different fat contents (i.e., 0, 15, 30%) and (b) creams with 15% fat but different fat characteristics. Skim milk and unhomogenized creams containing 15 and 30% fat were prepared from the same batch of whole milk and were carbonated at 0 and 40 degrees C in a continuous flow CO2 injection unit (230 ml/min). At 0 degree C, milk fat was mostly solid; at 40 degrees C, milk fat was liquid. At the same total CO2 concentration with CO2 injection at 0 degree C, milk with a higher fat content had a lower pH and FP, while with CO2 injection at 40 degrees C, milks with 0%, 15%, and 30% fat had the same pH. This indicated that less CO2 was dissolved in the fat portion of the milk when the CO2 was injected at 0 degree C than when it was injected at 40 degrees C. Three creams, 15% unhomogenized cream, 15% butter oil emulsion in skim milk, and 15% vegetable oil emulsion in skim milk were also carbonated and analyzed as described above. Vegetable oil was liquid at both 0 and 40 degrees C. At a CO2 injection temperature of 0 degree C, the 15% vegetable oil emulsion had a slightly higher pH than the 15% butter oil emulsion and the 15% unhomogenized cream, indicating that the liquid vegetable oil dissolved more CO2 than the mostly solid milk fat and butter oil. No difference in the pH or FP of the 15% unhomogenized cream and 15% butter oil emulsion was observed when CO2 was injected at 0 degree C, suggesting that homogenization or physical dispersion of milk fat globules did not influence the amount of CO2 dissolved in milk fat at a CO2 injection temperature of 0 degree C. At a CO2 injection temperature of 40 degrees C and at the same total CO2 concentration, the 15% unhomogenized cream, 15% vegetable oil emulsion, and 15% butter oil emulsion had similar pH. At the same total concentration of CO2 in cream, injection of CO2 at low temperature (i.e., < 4 degrees C) may produce a better antimicrobial effect during refrigerated shelf life due to the higher concentration of CO2 in the skim portion of the cream.