喷雾干燥对籽瓜种子蛋白理化及功能特性的影响

Effect of Spray Drying on the Physiochemical, Structural, and Functional Properties of Seed-watermelon Seed Proteins

摘要:

为探究喷雾干燥对籽瓜种子蛋白质理化结构及功能特性的影响。以冷冻干燥的籽瓜种子蛋白质作对比，探究喷雾干燥对蛋白质体积密度、色泽、体外消化率、氨基酸组成、热变性温度、表面疏水性、内源荧光、二级结构、超微结构及功能特性的影响。研究表明：与冷冻干燥相比，喷雾干燥后的籽瓜种子蛋白质体积密度较大为0.34 g/mL，白度较大，色泽较好，体外消化率较高为96.0%，赖氨酸与精氨酸比值较低为0.20，必需氨基酸组成基本没有变化，热稳定性较好，变性峰值温度、热变性焓值较大分别为89.06 ℃、1.751 J/g，内源荧光最大发射波长由352 nm向354 nm发生红移，表面疏水性增加为4097.5，β-转角含量增加为29.62%，α-螺旋、β-折叠和无规则卷曲均向β-转角转变，溶解性、持水持油性、乳化特性、起泡特性等功能特性均变差。

Abstract:

The aim was to explore the effect of spray drying on the physiochemical, structural, and functional properties of seed-watermelon seed proteins. The bulk density, color, in vitro digestibility, amino-acid composition, thermal denaturation, surface hydrophobicity, endogenous fluorescence, secondary structure, ultrastructure, and functional properties of spray-dried seed-watermelon seed proteins were compared to those of freeze-dried seed-watermelon seed proteins. The results showed that spray-dried seed-watermelon seed proteins had a larger bulk density (p=0.34 g/mL), greater whiteness, better color, higher in vitro digestibility (96%), a lower ratio of lysine and arginine (0.20), similar essential amino-acid composition, better thermal stability, a higher denaturation temperature (89.06°C), and a higher thermal denaturation enthalpy value (1.75 J/g) compared to the freeze-dried proteins. Additionally, spray-dried seed-watermelon seed proteins showed a red shift in the endogenous fluorescence maximum-emission wavelength from 352 nm to 354 nm, and increased surface hydrophobicity (4097.5) and β-turn content (29.62%). There was also a shift from the α- helix, β-sheet, and random coil secondary structures to β-turns, as well as a decrease in the solubility, water- and oil-holding capacities, emulsifying activity, and foaming properties.