Phytic Acid Degradation in Complementary Foods Using Phytase Naturally Occurring in Whole Grain Cereals

Complementary foods based on cereals and legumes often contain high amounts of phytic acid, a potent inhibitor of mineral and trace element absorption. The possibility to degrade phytic acid during the production of complementary foods by using whole grain cereals as the phytase source was investigated. Whole grain rye, wheat, or buckwheat (10%) were added to cereal‐legume‐based complementary food mixtures, and phytic acid was shown to be completely degraded in a relatively short time (1.5 to 3 h) when incubated at optimal conditions for cereal phytase. The potential usefulness of the method for industrial production was demonstrated with a complementary food based on wheat and soybean.     

克鲁斯假丝酵母植酸酶对植物性饲料中植酸的脱磷作用

在植物性饲料中,磷主要以植酸磷的形式存在,不能被单胃动物有效利用。在饲料中添加植酸酶,水解植酸脱磷,可以提高动物对磷的利用率。本文通过正交试验,确定了克鲁斯假丝酵母(CandidaKrusei)WZ 001植酸酶水解豆粕和麸皮中植酸脱磷的最适作用条件;并模拟动物胃肠pH环境,对克鲁斯假丝酵母WZ 001植酸酶和2种与其酶活相同的商品酶降解饲料中的植酸脱磷的能力进行了比较。结果表明:WZ 001植酸酶水解饲料植酸10h时释放的无机磷量是原游离磷的4.89倍,植酸水解率为67%,均高于酶活相同的2种商品酶。     

植酸酶对不同原料发酵乙醇的影响

本文考察以不同原料为底物时,在液化前添加植酸酶对液化粘度、DE值及后续发酵的影响。结果显示,当以全玉米粉为发酵底物,配料浓度为30%,植酸酶加量为10U·g-1干基时,液化及发酵效果最好,乙醇浓度可达15.38%(V/V),残糖指标相对也较低。使用全粉为原料时添加植酸酶对酒分提高显著。     

不同储藏条件下小麦粉植酸酶活性变化规律研究

在不同储藏条件下,对小麦粉中植酸酶活性变化规律进行研究。采用储藏条件为:相对湿度分别是55%和70%,温度分别为10℃、15℃、20℃、25℃、30℃、35℃,以此进行小麦粉模拟储藏试验。结果表明,小麦粉植酸酶活性为先快速上升,而后趋于平稳,继而下降;温度、时间对酶活性影响极其显著;小麦粉中植酸酶作用有限,大多数磷都以有机磷形式存在。     

玉米萌发植酸酶酶学特性的初步研究

研究了在玉米发芽过程中改变发芽温度、环境pH值、添加赤霉素和金属离子等培养条件对植酸酶活力的影响,确定了玉米发芽工艺条件:浸泡方式添加金属Ca2+离子,溶液pH4.0,发芽温度30℃,发芽48h.在此最佳条件下,植酸酶活力达到最大值为5.857U/g(绝干).     

聚乙烯醇环氧化载体制备及在植酸酶固定化中的应用

该文以聚乙烯醇为原料,利用戊二醛为交联剂,聚合得到交联球形聚乙烯醇,并将其与环氧氯丙烷反应用以固载环氧基团,得到可用于酶固定化的载体。讨论了交联聚乙烯醇球环氧基的固载条件和酶的固定化条件。植酸酶经过固定化后,机械性能和化学稳定性都得到提高,可以重复多次对植酸钠进行水解反应。同时对该自由酶和固定化酶进行酶学特性研究。发现自由酶和固定化酶的最适pH值分别为5.5和7.0,最适反应温度分别为55℃和70℃。植酸酶经固定化,提高了酶的操作、温度、pH值和贮藏稳定性。     

The effects of soaking of whole, dehulled and ground millet and soybean seeds on phytate degradation and Phy/Fe and Phy/Zn molar ratios

The degradation and leaching of phytates, phytase activity and iron and zinc concentrations have been studied after soaking of whole seeds, dehulled seeds and flours of millet and soybean, in order to investigate the efficiency of soaking on reducing Phy/Fe and Phy/Zn molar ratios. When using millet grains, dehulling and milling before soaking facilitated the leaching of phytates and phytases in the aqueous medium and hence phytate degradation. Dehulling of soybean seeds led to a marked increase in phytate content, whereas milling favoured reactions between phytases and phytates. The Phy/Fe and Phy/Zn molar ratios decreased only slightly during soaking. The highest decreases for millet were obtained after soaking of flour for 8 h (Phy/Fe: 10.8–7.7 and Phy/Zn: 20.3–15.1), and after soaking of whole seeds for 24 h for soybean (Phy/Fe: 10.4–9.4 and Phy/Zn: 23.8–19.1). Cooking of flours with water used for soaking did not increase phytate degradation.     

Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Phytic acid present in the raw materials can complex with many compounds and therefore limit their availability to the yeast during the alcoholic fermentation process. An effective utilization of biogenic compounds bound in phytates requires a detailed analysis of the raw materials for their phytic acid content. The aim of this study was to characterize the major technological parameters for selected raw materials used in the distilling industry (maize, rye, wheat and triticale grain) and to determine the phytic acid content and the IP6/total phosphorus ratio. The phytic acid hydrolysis rate during the mashing process, with the use of microbial phytases, was analysed. The highest phytic acid concentrations (2.30 ± 0.20 mg/g dry matter) and the highest IP6/total P (80.42 ± 6.99%) were observed in the maize grain samples. Therefore, further studies on the phytic acid hydrolysis rate with the use of various phytases were conducted for the maize grain. The highest hydrolytic activity was observed for the Phytase 10000L preparation. This was the preparation that hydrolysed the phytic acid completely in up to 90 min. The application of a highly effective phytase, in ethanol production from maize grain, could lead to a more effective utilization of the biogenic compounds during the fermentation process. Copyright © 2015 The Institute of Brewing & Distilling     

植酸酶的激光诱变改性与分离纯化

植酸酶产生菌———黑曲霉(Aspergillus niger)可在不同的辐照条件下进行激光诱变,确定了适宜的诱变条件,即输出波长为1.06μm的Nd:YAG高重复率声光调Q激光,辐照频率4 kHz,功率10 W,水平照射2~2.5m in,并建立了变异菌株基因库。通过高通量筛选,从中筛选到一株酶学性质比较符合工业生产要求的变异菌株phy226,pH=2~3的第二酶活峰提高了40%,酶活温度稳定在30~60℃。发酵液经盐析、透析、凝胶层析和离子交换层析等分离纯化过程,最终纯化倍数达7.8,收率为25.2%。