Natamycin and nisin to improve shelf life and minimize benzene generation in lemon soft drinks

Abstract Benzoic acids preservatives may be converted to benzene in soft drinks. The use of alternative antimicrobial compounds, specifically nisin and natamycin, would reduce benzene formation. Initially, doses of nisin and natamycin were tested against Lactobacillus plantarum lactic bacteria and Zygosaccharomyces bailii yeast. Using 167 UI/mL of nisin and 0.017% w/v of natamycin no microbial growth was reached on lemon-flavored soft drinks. The benzene formation was analyzed in a standard formulation (380 mg/L of sodium benzoate and 180 mg/L of potassium sorbate) and nisin and natamycn formulation (167 UI/mL of nisin and 0.017% w/v of natamycin). The soft drinks were stored without UV exposure at 20 °C and with UV sunlight exposure at 30 °C, for 120 days at PET bottles. The initial benzene content was 1.29 μg/kg for standard and 0.09 μg/kg for nisin and natamycin formulation; these values increased to 11.00 μg/kg and 0.18 μg/kg, respectively. The sensory attributes did not differ from each formulation, either initially or after 120 days of storage. The lower benzene concentrations obtained using nisin and natamycin suggest that these compounds are attractive alternatives to benzoic acids, keeping the sensory quality and microbial stability during shelf life.摘要：苯甲酸类防腐剂可在软饮料中转化为苯。采用替代抗菌化合物——尤其是乳链菌肽（nisin）与那他霉素（natamycin）——可有效降低苯的生成量。 本研究首先针对植物乳杆菌（Lactobacillus plantarum）与拜氏接合酵母（Zygosaccharomyces bailii），测试了乳链菌肽与那他霉素的使用剂量。在柠檬风味软饮料中，当使用167 UI/mL的乳链菌肽与0.017%质量体积比的那他霉素时，未检出微生物生长。 随后分别对标准配方（含380 mg/L苯甲酸钠与180 mg/L山梨酸钾）以及乳链菌肽-那他霉素配方（167 UI/mL乳链菌肽与0.017%质量体积比那他霉素）的苯生成情况进行了分析。将软饮料封装于PET瓶中，分别在20℃无紫外照射、30℃模拟太阳光紫外照射条件下储存120天。 结果显示，标准配方的初始苯含量为1.29 μg/kg，乳链菌肽-那他霉素配方的初始苯含量为0.09 μg/kg；储存120天后，二者的苯含量分别升至11.00 μg/kg与0.18 μg/kg。 两种配方在储存初期及储存期满后的感官属性均无显著差异。使用乳链菌肽与那他霉素得到的苯浓度更低，表明这两种化合物可作为苯甲酸类防腐剂的优质替代方案，在维持产品感官品质与货架期内微生物稳定性的同时，有效减少苯的生成。