青麦糕中微生物生长动力学模型及货架期研究

研究了一种新型全谷物糕点——青麦糕中微生物的生长动力学模型,并在此基础上对青麦糕货架期进行预测。对青麦糕在4、15、25℃条件下不同时间菌落总数和霉菌的生长情况进行研究,根据Gompertz模型建立4、15、25℃条件下青麦糕中菌落总数和霉菌的生长曲线模型,并建立Belehradek二级模型,研究温度对青麦糕中微生物生长动力学的影响。根据不同模型计算微生物生长动力学参数,并判断青麦糕中微生物的生长规律,进而预测青麦糕在不同贮藏条件下的货架期。结果表明:建立的模型能够很好地预测青麦糕中微生物的生长状态,对青麦糕在4、15、25℃条件下贮藏的菌落总数和霉菌的Gompertz模型进行拟合,R2均大于0.980 0,模型拟合良好。Belehradek二级模型的R2最小为0.868 7,说明温度与μm和λ的线性曲线适合Belehradek二级模型。通过验证,所有模型均可以可靠、快速地预测青麦糕的腐败程度和剩余货架期,从而保证青麦糕产品的食用品质和安全。

Study on microbial growth kinetic model and shelf life of green wheat cake

Green wheat is a traditional whole grain food in China with a history of more than 1,000 years.It is growing in popularity in Middle Eastern countries and worldwide. It contains 14. 90% protein,12. 88%dietary fiber and a large amount of vitamins and minerals,while starch and fat account for only 45. 17%and 1. 32%,respectively. Due to its low starch and high dietary fiber content,it is more suitable for people with diabetes and could replace staple food. Its nutritional value is much higher than wheat,and it also has great advantages in antioxidants. After harvesting,the green wheat was simply washed and quick-frozen at about-45 ℃,then stored at about-18 ℃ in order to inhibit microbial growth and prolong its shelf life.When making the green wheat cake,green wheat was thawed and cleaned. Then,the green wheat was vacuum freeze-dried and grounded into powder. Green wheat cake is a new type of whole grain cake which is obtained from green wheat flour and peeled mung bean flour( in the ratio of 7 ∶ 3) by steaming in a steamer with xylitol,butter and so on. Microbial prediction technology was used to study green wheat cakes microbial growth kinetic model,and on this basis,the shelf life of the green wheat cake was predicted. The growth of the total number of colonies and molds in the green wheat cake was determined at different storage time at 4,15 and 25 ℃. According to the Gompertz model,the growth curve model of the total number of colonies and molds in the green wheat cake at 4,15 and 25 ℃ was established. On this basis,the Belehradek secondary model was further established to study the influence of temperature on the growth kinetics of microorganisms in green wheat cake. Microbial growth kinetic parameters according to different models was calculated,and the growth law of microorganisms in the green wheat cake was judged. Then,the shelf life of the green wheat cake was predicted under different storage conditions. The results showed that the established model can predict the growth of microorganisms in green wheat cakes well. The results showed that the Gompertz model of the total number of colonies and molds stored in green wheat cakes at 4,15 and25 ℃ was fitted. The values of R2 were greater than 0. 980 0,therefore,the model fitted well. The minimum R2 of the Belehradek second-level model was 0. 868 7,indicating that the linear curves of temperature and μm and λ are suitable for the Belehradek second-level model. Through verification,all models can reliably and quickly predict the spoilage and remaining shelf life of green wheat cakes,thereby ensuring the edible quality and safety of green wheat cakes.