国产巧克力球回软问题的研究

Research of softening of the chocolate balls made in China

为探索国产巧克力球储存后回软的原因,分别采用核磁共振法、气相色谱法和水分活度测定仪法测定巧克力球内外层固体脂肪含量(SFC)、内外层脂肪酸组成以及威化层的水分活度。在不同温度条件下,国产巧克力球外层SFC均低于参照样(40℃除外),且随着储藏时间的延长而降低(<20℃)。内层在较低温度时(<17℃),随储藏期的延长而降低,而在较高温度时(>17℃)则呈相反趋势。两者内外层主要脂肪酸含量相当,但反式脂肪酸含量为参照样的1.6倍。另国产巧克力球威化层的水分活度较高,且随着储藏时间的延长逐渐增大。本研究表明,国产巧克力球外层巧克力的固体脂肪在储藏过程中向内层迁移,选料差异以及外涂层的密封性等原因可能共同导致了巧克力球储藏过程中的回软现象。

To explore the reasons for the softening of the domestic chocolate balls, NMR, gas chromatography and Aw tester were employed to detect the solid fat content （SFC） and fatty acid composition of the internal and external layers and water activity in the wafer layer.The SFC in external layer of the domestic chocolate balls was lower than that of the imported chocolate balls（control） （except for 40%） ,and the SFC decreased along with the increasing of storage period （ 〈 20℃）.As to the SFC in internal layer, it decreased along with the increasing of storage period at the low temperature（ 〈 17℃）, but the trend was opposite at the high temperature（ 〉 17℃）.The main fatty acid contents in the external layer of the domestic products and the control were close to each other.The trans fatty acid of the domestic products was 1.6 times of the control.The water activity in biscuit layer of the domestic products was higher and increased with the increasing of storage period.It could be concluded that the solid fat in external layer would move into the internal layer during the storage period, furthermore, the internal materials of the domestic chocolate balls and the reference were different, and these may be the reasons for softening.