Composition and bioavailability of oxalates in baked taro (Colocasia esculenta var. Schott) leaves eaten with cows milk and cows milk and coconut milk

Taro leaves are an important food in the Pacific Islands but the overall oxalate composition and its nutritional effect has not been investigated. The oxalate contents of taro leaves were determined using chemical and in vitro extraction methods. Maori‐type taro leaves contained 524.2 ± 21.3 mg total oxalates 100 g^?1 fresh weight (FW) and 241.1 ± 20.9 mg soluble oxalates 100 g^?1 FW while the Japanese‐type leaves contained 525.6 ± 19.9 mg total oxalates 100 g^?1 FW and 330.4 ± 28.3 mg soluble oxalates 100 g^?1 FW. Maori‐type taro leaves contained 416.4 ± 1.5 mg gastric soluble oxalates 100 g^?1 FW and 212.4 ± 34.8 mg intestinal soluble oxalates 100 g^?1 FW while the Japanese‐type leaves contained 433.3 ± 9.7 mg gastric soluble oxalates 100 g^?1 FW and 224.2 ± 38.7 mg intestinal soluble oxalates 100 g^?1 FW). Human feeding experiments were conducted to determine the availability of the oxalates in the baked leaves following additions of cows milk and coconut milk. The consumption of a test meal of baked taro leaves resulted in a significant increase (P < 0.001) in the output of urinary oxalate in the following 6 h when compared to the output of oxalate during a reference collection. When the leaves were baked with cows milk or cows milk and coconut milk combined and consumed there was a small non‐significant reduction in urinary oxalate output which suggests that less soluble oxalate was absorbed from these mixtures.     

Role of Long Noncoding RNAs ZlMSTRG.11348 and UeMSTRG.02678 in Temperature-Dependent Culm Swelling in Zizania latifolia

Temperature influences the physiological processes and ecology of both hosts and endophytes; however, it remains unclear how long noncoding RNAs (lncRNAs) modulate the consequences of temperature-dependent changes in host–pathogen interactions. To explore the role of lncRNAs in culm gall formation induced by the smut fungus Ustilago esculenta in Zizania latifolia, we employed RNA sequencing to identify lncRNAs and their potential cis-targets in Z. latifolia and U. esculenta under different temperatures. In Z. latifolia and U. esculenta, we identified 3194 and 173 lncRNAs as well as 126 and four potential target genes for differentially expressed lncRNAs, respectively. Further function and expression analysis revealed that lncRNA ZlMSTRG.11348 regulates amino acid metabolism in Z. latifolia and lncRNA UeMSTRG.02678 regulates amino acid transport in U. esculenta. The plant defence response was also found to be regulated by lncRNAs and suppressed in Z. latifolia infected with U. esculenta grown at 25 °C, which may result from the expression of effector genes in U. esculenta. Moreover, in Z. latifolia infected with U. esculenta, the expression of genes related to phytohormones was altered under different temperatures. Our results demonstrate that lncRNAs are important components of the regulatory networks in plant-microbe-environment interactions, and may play a part in regulating culm swelling in Z. latifolia plants.     

Production of a Lactobacillus plantarum starter with linamarase and amylase activities for cassava fermentation

Lactobacillus plantarum strain A6 isolated from cassava, cultured on cellobiose MRS medium showed a growth rate of 0.41 h^?1, a biomass yield of 0.22 g g^?1, and produced simultaneously an intracellular linamarase (76.4 U g^?1 of biomass) and an extracellular amylase (36 U ml^?1). The synthesis of both enzymes was repressed by glucose. The use of such a strain as a cassava fermentation starter for gari production had the following influences: a change from a hetero-fermentative pattern observed in natural fermentation to a homofermentation, a lower final pH, a faster pH decline rate and a greater production of lactic acid (50 g kg^?1 DM). However, this starter did not appear to play a significant role in cassava detoxification, since it was observed that the level of endogenous linamarase released during the grating of the roots was sufficient to permit the complete and rapid breakdown of linamarin.     

Reduction of cyanide levels during anaerobic digestion of cassava

During the methanogenic fermentation of cassava peel in a plug flow digester, cyanide bound as linamarin in cassava was released as HCN in the fermentation liquor, and then eliminated by the activity of free enzymes and by non-enzymatic reactions. The raw cassava peel contained (1) the enzyme permitting the hydrolysis of linamarin and the liberation of HCN (linamarase), and (2) a cyanide detoxification enzyme (β-cyanoalanine synthase). Cyanide removal was sufficiently fast to maintain a cyanide concentration in the fermentation liquor which was non-inhibitory for the methanogenic microflora.     

Total cyanide levels in bread made from wheat/cassava composite flours

Cyanide levels were determined in cassava flours and bread. It was found that incubation media had no effect on cyanide determination. For all the cyanide to be released, incubation was carried out with linamarase extract for 14 h, followed by prolonged aeration of the media. Cassava flour with low initial levels of HCN gave cyanide-free bread, whereas there was a retention of 8% of the original HCN in loaves obtained from cassava flours with initial high levels of HCN.     

香芋淀粉糊的特性

研究了糊浓度、温度、回转速度、pH和盐等因素对香芋淀粉糊粘度的影响 ,测定了香芋淀粉糊的透光率、冻融性、凝沉性和抗霉菌能力等性质。结果表明 ,香芋淀粉糊具有透明度低 ,冻融稳定性差 ,沉降性好等性质。在酸性条件下 ,淀粉糊粘度迅速下降 ;在中性条件下 ,糊粘度最高。不同的盐对淀粉糊的影响不同 ,其中硼砂和一些过渡金属盐的存在使糊粘度升高。     

香芋淀粉磷酸酯的糊化特性研究

研究了香芋淀粉磷酸酯的糊黏度、透明度、冻融稳定性、沉降稳定性、糊化难易程度、耐糖、耐盐和抗霉菌能力。结果表明,与原淀粉相比,香芋淀粉磷酸酯更容易糊化,透明度高,沉降稳定性好,冻融稳定性和抗霉菌能力有所改善,糊黏度减小。随着取代度的增加,香芋淀粉磷酸酯的糊化变得容易,耐盐和耐糖能力提高;透明度先增后减;糊黏度则先减后增。取代度的变化对沉降性和抗霉菌能力影响不大。     

羊肚菌多酚氧化酶性质的研究

本文研究了温度、pH值等对羊肚菌多酚氧化酶(MEPPO)活力的影响及其热稳定性和以邻苯二酚为底物的动力学。结果表明：MEPPO最适反应温度为50℃；温度低于60℃时，MEPPO的稳定性较高，而在70℃保温4h时，活性几乎完全丧失；MEPPO最适pH值为7．0；以邻苯二酚为底物的最大反应速度Vmax=0．02AA／min，Km=0．00588。