苯甲酸钠对新鲜果汁保鲜效果的研究

Preservative Effects of Sodium Benzoate on Fresh Crude Juices

为了明确苯甲酸钠在新鲜果汁保鲜中的效果,以苹果汁、雪梨汁和菠萝汁3种常见果汁为研究对象,通过微生物的生长参数分析,确定微生物生长的临界浓度,并通过维生素C含量的变化指标评估苯甲酸钠的加入对新鲜果汁营养指标的影响。结果表明,苯甲酸钠对苹果汁、雪梨汁和菠萝汁的微生物生长临界浓度分别为0.08%、0.10%和0.06%。苯甲酸钠对菠萝汁有良好保鲜效果,苹果汁次之,而雪梨汁的微生物生长临界浓度已达到国家规定的上限,不推荐使用苯甲酸钠作为其保鲜剂。维生素C含量的变化指标表明,在保藏初期,苯甲酸钠的加入增加了维生素C的不稳定性,加速了果汁中维生素C含量的降低;但在保藏后期,添加苯甲酸钠的样品汁维生素C含量要高于未添加苯甲酸钠的样品汁,所以苯甲酸钠的存在虽然增加了维生素C的不稳定性,但从整个保藏周期来看,其存在可减缓维生素C含量的降低。

To investigate the preservative effects of sodium benzoate on fresh juices, three types of fresh juices including ap- ple, pear and pineapple were used to study the critical growth concentrations of sodium benzoate for microbes with the mi- crobiology growth parameter. Effects of benzoate on juice＇s nutrition index were studied through the changes of vitamin C content. The results showed that the critical growth concentrations of sodium benzoate for microbes in fresh juices of apple, pear and pineapple was 0.08%, 0.10% and 0.06%, respectively. Sodium Benzoate had the highest preservative effects on the pineapple juices, followed by apple juices. But sodium benzoate was not recommended to be used for pear juices preservation since its critical growth concentrations in pear juices reached the upper limit of national standard. The change of VC con- tents also showed that sodium benzoate increased the vitamin C unstable and accelerated the decrease of the vitamin C con- tent in the initial phase of preservation. In the final period of preservating, the vitamin C content of juice with sodium ben- zoate was higher than that of those juices without sodium benzoate. It is indicated that the sodium benzoate could slow down the reduction of vitamin C content during the whole preservation.