L-半胱氨酸对香菇贮藏过程中内源性甲醛的转化及子实体品质的影响

目的 研究L-半胱氨酸处理对香菇贮藏过程中内源性甲醛的转化及子实体品质的影响。方法 香菇经L-半胱氨酸浸泡后,于4℃下密封贮藏,并监测其在贮藏期间甲醛含量、硫杂脯氨酸含量、褐变度、多酚氧化酶(Polyphenol Oxidase,PPO)活性、可溶性蛋白质含量、还原糖含量的变化。结果 L-半胱氨酸处理后,香菇子实体的甲醛含量显著低于对照组,并伴随着硫杂脯氨酸的生成,且硫杂脯氨酸的生成量与甲醛的消耗量达到显著正相关;贮藏期间,L-半胱氨酸处理组可显著抑制PPO酶活性的上升、减缓子实体的褐变速度;进一步的研究显示,L-半胱氨酸处理后香菇子实体的还原糖、可溶性蛋白质含量均高于对照组。结论 L-半胱氨酸可与香菇内源性甲醛生成硫杂脯氨酸,抑制子实体褐变和PPO活性,延缓还原糖和可溶性蛋白的降解,具备较好的甲醛清除和保鲜作用。     

微波辅助提取香菇柄水溶性膳食纤维的工艺研究

以香菇柄为原料,利用微波辅助法提取其中的水溶性膳食纤维,采用正交试验对香菇柄水溶性膳食纤维的提取工艺进行优化。结果表明,香菇柄水溶性膳食纤维的最佳提取工艺条件为:柠檬酸质量分数为5%、料液比1∶20、微波功率640 W、微波处理时间3 min。在此最佳条件下,香菇柄水溶性膳食纤维的平均得率为10.24%,持水力为2.27 g/g,膨胀力为4.13 m L/g。     

香菇菌丝深层发酵及多糖提取分离研究

采用液体发酵培养的方法获得香菇发酵液(LEL),发酵液经离心,提取得胞内粗多糖(LEPI),再经DEAE柱层析得到一种蛋白多糖复合物,然后用Supdex200凝胶层析显示为单峰。     

Antioxidant properties of fungal chitosan from shiitake stipes

Fungal chitosan B or C was prepared by alkaline N-deacetylation of crude chitin B or C for 60, 90 and 120 min, which was obtained from air-dried shiitake stipes and its antioxidant properties studied. Chitosan showed antioxidant activities of 61.6-82.4% at 1 mg/ml and showed reducing powers of 0.42-0.57 at 10 mg/ml. At 10 mg/ml, scavenging abilities of chitosan B60 and C60 on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were 28.4-31.3% whereas those of chitosan B90, B120, C90 and C120 were 44.5-53.5%. With regard to the scavenging ability on hydroxyl radicals at 0.1 mg/ml, chitosan B60 and C60 were 61.9% and 63.6%, chitosan B90 and C90 were 68.3% and 69.9% and chitosan B120 and C120 were 77.7% and 77.2%, respectively. At 1.0 mg/ml, chelating abilities of chitosan B60 and C60 on ferrous ions were 88.7-90.3% whereas those of the rest chitosan were 97.8-103%. EC₅₀ values of antioxidant activity were below 1 mg/ml whereas those of reducing powers and scavenging abilities on DPPH radicals were 7.69-16.3 mg/ml. EC₅₀ values of scavenging abilities on hydroxyl radicals were below 0.1 mg/ml whereas those of chelating abilities on ferrous ions were 0.58-0.69 mg/ml.     

香菇柄发酵酱营养品质及风味成分研究

该研究在传统发酵酱的基础上,添加香菇柄粉制备香菇柄发酵酱,并对其进行水分、还原糖、氨基酸态氮、红色指数及氨基酸等指标测定,采用气相色谱-离子迁移谱联用（GC-IMS）技术分析其挥发性风味成分。结果表明,香菇柄发酵酱中还原糖含量（21.12%）及红色指数（1.44）均明显高于传统发酵酱,其水分含量（62.79%）及氨基酸态氮含量（0.76%）稍低于传统发酵酱。两种发酵酱中均测出17种氨基酸（包含7种必需氨基酸）,传统发酵酱、香菇柄发酵酱氨基酸总量分别为99.09 mg/g、87.71 mg/g,且两种发酵酱中呈味氨基酸比例相似。两种发酵酱均共检测出32种挥发性成分,包括醇类8种、醛类9种、酯类3种、酮类4种、酸类3种、吡嗪类2种、呋喃类2种、醚类1种。研究表明,香菇柄发酵酱品质符合国标GB 2718—2014《酿造酱》的要求。     

香菇冻结规律及品质变化研究

研究了香菇在不同低温条件下的冻结规律及品质的变化,探讨了香菇在不同冻结条件下多酚氧化酶、维生素C和感官质量等指标的变化。实验结果表明,香菇在-27℃以上的温度达不到速冻要求;香菇最适宜的冻结条件为-37～-40℃。     

发酵型香菇保健醋饮料的研制及营养分析

介绍了以马铃薯等为主要原料,经过香菇发酵、酒精发酵和醋酸发酵等多步,将原料中的有关物质转化成食用菌保健醋中的有效成分,从而生产出香菇醋,这种醋富含氨基酸及真菌多糖,具有一定的保健功能,再通过调配而将其制成保健醋饮料。     

Cultivation of the shiitake mushroom (Lentinus edodes) on lignocellulosic waste

The Shiitake mushroom (Lentinus edodes) was successfully grown and fruited on a substrate containing 7 parts hardwood sawdust and 3 parts oatmeal. Colonised blocks of substrate placed in a fruiting environment produced edible mushrooms in 9–15 days with an average total yield of c. 135% fresh weight mushrooms per unit dry weight of substrate. The mushroom fruited when daily temperatures ranged between 11 and 26°C.     

不同蛋白酶对香菇酶解液性质的影响

选用碱性蛋白酶、风味蛋白酶和中性蛋白酶水解香菇粉,研究不同蛋白酶对香菇酶解液的水解度、营养成分、感官评价和挥发性风味物质的影响。结果表明,随着酶解时间的延长,三种酶解液的水解度先升高后降低,风味蛋白酶酶解4 h的酶解液水解度最高,达到26.03%;酶解液的可溶性蛋白质含量、多糖含量及鲜味和香菇特征风味在酶解过程中的变化趋势与水解度类似,其中碱性蛋白酶酶解液多糖含量较高、苦味最明显,风味蛋白酶酶解液可溶性蛋白质含量较高、苦味整体最弱,4 h的酶解液的整体感官评分最高,为22.80分。气相色谱-质谱联用（GC-MS）分析三种蛋白酶解液共检出30种挥发性风味物质,其中含硫化合物相对含量占绝对优势,均高达90%以上,对风味的贡献最大;醛类物质种类最多,含量仅次于含硫化合物,其中风味蛋白酶解液中醛类物质相对含量最高。因此,风味蛋白酶酶解液水解度、营养成分更高,且整体风味更好。