燕麦耐消化肽纳米载体的制备表征及其对咖啡酸苯乙酯的包埋作用研究

为提高燕麦蛋白的水溶性并提高其在纳米材料领域的应用价值,通过酶水解法制备了燕麦耐消化肽纳米颗粒,并评估其包封疏水活性物质的能力及耐消化特性。燕麦蛋白经胃蛋白酶和胰蛋白酶消化制备出燕麦肽纳米颗粒,为50 nm的球形胶束。燕麦蛋白经过胃蛋白酶消化水解度为3.1%,胰蛋白酶消化水解度为10.7%。对内部相互作用进行分析表明,燕麦肽纳米颗粒主要由疏水作用驱动自组装,氢键和二硫键对维持结构稳定有一定作用。表面活性研究表明,燕麦肽纳米颗粒表面具有一定的疏水性和亲油性,水解改性大大增强了纳米颗粒的水溶性。以咖啡酸苯乙酯为模型药物评估燕麦肽纳米颗粒的载药性能,包封率为71%,载药量为3.5%,咖啡酸苯乙酯在水中的质量浓度从1.8提升至140μg/mL。载药纳米颗粒体外模拟消化结果表明,耐消化肽纳米颗粒具有较强的耐消化特性,在胃肠液中咖啡酸苯乙酯的释放率低。稳态荧光光谱分析表明,疏水相互作用是咖啡酸苯乙酯与肽分子结合的主要作用力。研究表明,燕麦肽纳米颗粒是增加疏水物质溶解度的良好载体。

可消化耐嚼糖果的制作工艺比较

分别采用两种工艺研制新型耐嚼糖果，通过理化检测、感官分析及成本比较，确定了最佳方法。采用该法研制的新型糖果，咀嚼时间长，口感类似胶姆糖，有较好的粘弹性和硬度，可被人体完全消化代谢。

新型可消化耐嚼糖果的研究

通过单因素试验及多因素正交试验、复配试验 ,确定了可消化耐嚼糖果的配方原料 ,并对原料的配方进行了优化 ,研制出一种富营养、抗龋齿、耐咀嚼、口感类似胶姆糖的可消化新型糖果。

不同分子特性玉米蛋白高F值活性肽的制备及其模拟消化吸收

以玉米黄粉为原料,通过碱性蛋白酶和风味蛋白酶复合酶解制备玉米蛋白高F值活性肽(High Fischer ratio peptide,HFRP),同时根据分子量、电荷性和疏水性差异将HFRP进行分离纯化,并对其吸收特性和耐胃肠消化特性进行探究。结果表明:通过复合酶解法对玉米黄粉进行水解,得到HFRP(F值=26.29)。将HFRP分别按照分子量、电荷性和疏水性进行分离、收集,得到12种组分。通过构建Caco-2细胞体外吸收模型,研究不同分子特性组分的吸收状况,采用质谱扫描鉴定出质荷比(m/z)分别为203.1409、229.2980、226.9517、284.2966的高吸收短肽LA、IP、PL、HQ;通过研究不同分子特性组分的胃肠消化状况,采用质谱扫描鉴定出质荷比(m/z)分别为226.9517、284.2966的耐消化短肽PL和HQ。短肽PL和HQ分子量小,疏水性高,在溶液中带有正电荷,具有优先吸收和耐胃肠消化的特点。本研究为玉米蛋白高F值活性肽的开发提供了理论依据。

高F值活性肽的生物活性、制备技术及吸收评价技术的研究进展

高F值活性肽(HFRP)是指一类由2~9个氨基酸残基所组成的小肽，一般F值大于20。HFRP是一种重要活性肽，具有抗疲劳，补充人体必需氨基酸，促进酒精代谢，保肝护肝，促进氮储留和蛋白质合成，抑制蛋白质分解，改善手术后和卧床病人的蛋白营养状况等多种生理功能，因此具有良好开发应用前景。本文综述了高F值活性肽的生理功能及用途、原料及制备技术、耐消化性及肠吸收评价技术的研究进展，为新型活性肽保健食品的研究开发提供理论依据和技术支持。

Molecularly defined adult-type hypolactasia among working age people with reference to milk consumption and gastrointestinal symptoms

AIM: To study milk consumption and subjective milk- related symptoms in adults genotyped for adult-type hypolactasia. METHODS: A total of 1900 Finnish adults were genotyped for the C/T-13910 variant of adult-type hypolactasia and filled in a structured questionnaire concerning milk consumption and gastrointestinal problems. RESULTS: The C/C-13910 genotype of adult-type hypolactasia was present in 18% of the study population. The prevalence of the C/C-13910 genotype was higher among subjects who were undergoing investigations because of abdominal symptoms (24%, P < 0.05). Those with the C/C-13910 genotype drank less milk than subjects with either the C/T-13910 or the T/T-13910 genotype of lactase persistence (18% vs 38%; 18% vs 36%, P < 0.01). Subjects with the C/C-13910 genotype had experienced more gastrointestinal symptoms (84%) during the preceding three-month period than those with the C/T-13910 (79%, P < 0.05) or the T/T-13910 genotype (78 %, P < 0.05). Only 9% (29/338) of the subjects with the C/C-13910 genotype consumed milk and reported no symptoms from it.CONCLUSION: Gastrointestinal symptoms are more common among adults with the C/C-13910 genotype of adult-type hypolactasia than in those with genotypes of lactase persistence.

The Survival of Cefazolin Resistant Bacteria in Thermophilic Co-digestion of Dairy Manure and Waste Milk

Recent studies have suggested that there may be a link between the use of in-feed antibiotics and the prevalence of antibiotic-resistant bacteria in human infections. It is believed that anaerobic digestion is a potent method to reduce the antibiotic resistant bacteria present in waste from concentrated animal feeding operations. Cefazolin is a β-1actam antibiotic that is frequently used to treat the cows with mastitis in the Obihiro University herd. Disposal of untreated milk containing cefazolin residues promotes the occurrence of cefazolin resistant bacteria in the vicinity of farm, thus the objective of this study was to investigate the survival of antibiotic resistant bacteria in co-digestion of dairy manure and waste milk obtained from cows treated for mastitis with cefazolin under thermophilic conditions （55 ~C）. Cow manure, digested slurry and waste milk （cefazolin residue concentration 2.17 mg/L） were used as the materials in order to have three digester contents; 100% slurry, 50% slurry ＋ 50% manure and 50% slurry ＋ 45% manure ＋ 5% waste milk. The experiment was carried out using batch digesters （1 L） with active volume of 800 mL at 55 ℃ for 20 days to determine the survival of cefazolin resistant bacteria and to observe the digester performance by determining the bio gas and methane yield using gas chromatpgrapby. Dilution plate method was used to determine the population densities of total and cefazolin resistant bacteria at 0, 10th and 20th day of digestion. Total and cefazolin resistant bacterial counts were reduced with time by several orders until 10th day of digestion and those were almost similar at day 20th. Highest daily biogas and methane yield were observed in the digester contained slurry, manure and waste milk during early digestion period （until 5th day）. The results suggest that thermophilic co-digestion of dairy manure and waste milk would be a suitable technology for reducing antibiotic （cefazolin） resistant bacteria while obtaining better digester performance.

Thermal preference, thermal tolerance and the thermal dependence of digestive performance in two Phrynocephalus lizards （Agamidae）, with a review of species studied

We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards （P. frontalis and P. versicolor）, and compared data among lizards so far studied worldwide. Mean values for selected body temperature （Tsel） and critical thermal maximum （CTMax） were greater in P versicolor, whereas mean values for critical thermal minimum （CTMin） did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient （ADC） and assimilation efficiency （AE）, across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards