生乳与UHT灭菌乳中糠氨酸含量及其测定方法研究

本文研究了生乳与UHT灭菌乳中糠氨酸含量及其测定方法,并提出糠氨酸作为UHT灭菌乳中复原乳成分的标示物质,以鉴定UHT灭菌乳中是否掺入复原乳。结果表明,生乳中糠氨酸含量低于7mg/hg(按蛋白质计);乳粉中糠氨酸含量大于135mg/hg,不含复原乳的UHT灭菌乳中糠氨酸含量应小于140mg/hg(按蛋白质计)。使用高效液相色谱(HPLC)紫外检测糠氨酸含量,平均偏差<5%(n=5);回收率为98.2%。     

Significance of furosine as heat-induced marker in cookies

The effects of recipe formulation in terms of leavening agents (ammonium and sodium bicarbonates), sugars (sucrose and glucose), initial moisture content, and baking conditions (temperature and time) on furosine formation in cookies were studied. The cookies were baked at different temperatures for different times to monitor the progress of the early stage of the Maillard reaction. Change in furosine levels as an indicator of the Amadori products showed a typical kinetic behavior with a rapid increase to an apparent maximum followed by exponential decrease during baking. Initial water activity of cookie dough had no remarkable effect on the apparent maximum, but lowering the water activity decreased the time required to attain it. In addition, levels of furosine in the final product are highly correlated to the initial water content of dough at the same baking conditions. The levels of furosine attained were significantly lower in cookies composed of sucrose than in cookies composed of glucose. Early stage of the MR is rapidly overcome during baking as the Amadori product degraded in the advanced stage. Among the leavening agents, ammonium bicarbonate was the most effective for the progress of the Maillard reaction in cookies during baking.     

Formation of Glycated Products and Quality Attributes of Shrimp Patties Affected by Different Cooking Conditions

ABSTRACT

The objective of this study was to firstly investigate the impact of the cooking conditions, including boiled, baked, and microwaved treatments, in the presence of 3% powdered sugar and 1% NaCl on the changes of quality attributes and the formation of glycated products in shrimp patties. The levels of carboxymethyllysine (CML), furosine, and fluorescent intensity in boiled shrimp patties were much lower than that in baked shrimp patties and microwaved shrimp patties. Addition of powdered sugar alone in baked shrimp patties and microwaved shrimp patties increased the level of furosine and fluorescent intensity. Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed a notably decreased intensity in the band with MW of 17–22 kDa in boiled shrimp patties and microwaved shrimp patties, and a stronger intensity of band, with MW of 75–100 kDa, in baked shrimp patties. Principal components analysis (PCA) further confirmed that the changes of quality attributes and glycated products in shrimp patties caused by cooking methods were greater than that caused by the addition of powdered sugar or NaCl.     

呋甾烷研究进展

呋甾烷是食品、中药材（药品）储存和炮制以及人体内非酶糖基化反应（Mallard反应）的糖基化终产物之一,与食品营养、中药材（药品）品质和人体健康密切相关.因此,对呋甾烷进行全面、深刻研究具有重要意义.对呋甾烷生化特性与结构、生成机理、测试方法和抑制策略4部分进行简要综述,并在此基础上对呋甾烷研究前景进行展望,以期为呋甾烷后期研究提供一定参考.     

Effects of extrusion cooking conditions and chemical leavening agents on lysine loss as determined by furosine content in corn based extrudates

The aim of this study was to investigate the effects of different variables on lysine loss as determined by furosine content in corn-based extrudates. Three formulations were prepared to study the effects of different chemical leavening agents, processing conditions (feed moisture content: 22, 24 or 26%; exit die temperature: 110 or 150 °C), and extrusion cooking methods (with/without CO₂ injection) on furosine formation. Furosine levels of extrudates from both extrusion methods decreased around 20% when feed moisture content was increased from 22% to 26%. Amadori compounds (precursor of furosine) are formed in the early stages of the Maillard reaction, and later they are converted to further products. Consequently, furosine contents of extrudates significantly decreased as exit die temperature increased from 110 to 150 °C. Furosine contents of extrudates produced with sodium- and ammonium-bicarbonate at 150 °C exit die temperature significantly decreased, while the ones produced at 110 °C significantly increased. This may be due to accelerated formation of fructosyllysine at higher pH values followed by early degradation at 150 °C. The CO₂ injection method did not have a significantly different effect on furosine content of extrudates than that produced by the conventional extrusion method, but had a positive effect on the physical properties of extrudates.