块菌红酒的抗氧化活性研究

分别测定了块菌乙醇提取液、自制红葡萄酒清除自由基的抗氧化活性能力,以及块菌乙醇提取液和自制红葡萄酒两者不同比例混合液清除自由基的抗氧化活性能力。结果表明,块菌乙醇提取液、自制红葡萄酒均有较好的抗氧化活性,而两者不同比例的混合液则有更高的抗氧化活性。     

块菌酒主发酵工艺条件优化研究

以印度块菌和糯米为主要原料,在单因素实验基础上,经过优化工艺技术参数,用正交实验设计对块菌发酵酒进行研究。结果表明:糯米最佳的糖化时间为6h,糖化酶添加量为0.3%,糖化温度为60℃,主发酵最佳发酵温度为24℃,酵母接种量1%,初始糖度210g/L,发酵时间为6d;所得块菌发酵酒澄清透明,滋味醇厚自然,香气怡人,并且氨基酸种类齐全,总量很高,赋予了其很高的营养价值。      

块菌多糖复合酶法提取工艺优化

以印度块菌为原料,运用复合酶法提取块菌多糖。采用单因素和均匀试验设计方法,考察酶配比、酶解时间、酶解温度、酶用量、料液比、pH值6个因素对块菌多糖得率的影响。按照U_(10)(10~8)进行试验,考察各因素及其交互作用对块菌多糖得率的影响,预测和验证最佳工艺参数。结果表明:块菌多糖提取的最佳工艺条件为中性蛋白酶与纤维素酶1:7(g/g)、酶解时间48min、酶解温度41℃、酶用量3.6%、料液比1:29 (g/mL)、酶解pH值4.8,多糖得率可达14.50%,含量可达75.96%。经验证,该工艺稳定可行,适用于块菌多糖的提取。     

黑松露多糖分离纯化与抗炎活性研究

以黑松露为原料,通过水提醇沉法提取黑松露多糖。提取的黑松露多糖经过DEAE Sepharose Fast Flow离子交换层析柱分离得到两个块菌多糖组分,分别为TP1和TP2。检测TP1和TP2对小鼠巨噬细胞(RAW264.7)增殖抑制作用、中性红吞噬能力影响。TP1进一步用葡聚糖凝胶层析柱纯化,得TP1-1并进行结构表征。结果表明:黑松露多糖两种组分TP1和TP2对RAW264.7细胞没有毒性作用,且都能显著增强RAW264.7细胞的中性红吞噬能力,但TP1的作用优于TP2。TP1-1的数均分子量为757910 u,其单糖组成为D-葡萄糖和D-甘露糖,比例分别为88.94%和1.19%。紫外光谱扫描结果显示块菌多糖TP1-1不含蛋白质和核酸。红外光谱分析结果表明,TP1-1具有吡喃环的结构,具有α-型糖苷键,含有甘露糖。     

Aroma-volatile profile and its changes in Australian grown black Périgord truffle (Tuber melanosporum) during storage

Black Périgord truffle (Tuber melanosporum) is one of the most expensive fungi in the world that appreciated by gourmets. Studies have indicated the impact of growing location and soil microorganisms on the aroma profile of truffle. The aroma profile of West Australian black Périgord truffle (Tuber melanosporum) has not been previously reported, which was studied over a 14 day storage period. Sixty-four compounds were identified in all truffle samples. Significant changes (P > 0.05) were observed in 11 key volatiles (carbon dioxide, acetaldehyde, 2-butanone, 3-methyl-1-butanal, toluene, 2-butenal, formic acid 2-methyl butyl ester, 3-methyl-1-butanol, 6-methyl-2-heptanol, 3-octanol and dimethyl sulfoxide) over time. Comparison of these results against published aroma profile of European grown black Périgord truffle identified number of significant similarities and differences were also detected. Dimethyl sulfoxide, a compound previously identified in European grown white truffle (Tuber magnatum), was detected. Principle component analysis (PCA) showed that the major changes in the truffle aroma profile took place in the first 7 days of storage.     

Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review

Truffles are considered one of the world's most highly prized foods mainly due to their desirable organoleptic properties and rarity. However, truffles are seasonal (harvested mostly in winter from June to August in the Southern Hemisphere and from December to February in the Northern Hemisphere) and extremely perishable. Truffles deteriorate rapidly showing undesirable changes within 10 days from harvest in aroma and visual appearance after harvest. The very short postharvest shelf life (about 7–10 days) limits the potential for export and domestic consumption all year round. Several preservation methods have been studied to prolong their shelf life without the loss of aroma. However, all traditional preservation techniques have their own shortcomings and remain challenging. The extraction of natural truffle aroma volatiles for food applications could be a potential alternative to replace the existing synthetic flavoring used for processed truffle products. Four commonly used extraction methods for recovering volatile compounds from plants, namely, supercritical carbon dioxide extraction, Soxhlet extraction, distillation, and cold pressing, are critically analyzed. Up to date, existing research about the extraction of aroma volatiles from truffles is limited in the literature but based on the volatility of the key truffle volatile compounds, supercritical carbon dioxide extraction may offer the best possibility so that a natural truffle-based product that can be used in food applications throughout the year can be made available.     

The application of Borneo tallow in dark chocolate shell

Dark chocolate shells, formulated using cocoa butter (CB shell), and fat blends containing 15% Borneo tallow (IP) in cocoa butter (CBIP shell), were filled with truffles formulated using white chocolate (W truffle), milk chocolate (M truffle) and dark chocolate (D truffle). Anhydrous milk fat (AMF) content of the W truffles, M truffle and D truffle were 26·3%, 13·7% and 9·2%, respectively. Degree of tempering was determined using a tempermeter. The chocolates were kept at ambient temperature (25·5±0·5°C) for 3 months. Physical changes of chocolate shells and centres were monitored using DSC and a texture analyser. Results showed that the CBIP shell had to be tempered at 32·5%, ie 1°C higher than the normal CB shell. Physical measurements indicated the occurrence of fat migration. The presence of IP reduced the effect and increased the bloom resistance of the chocolate. © 1998 SCI.