Effect of Humidity-Controlled Dehydration on Microbial Growth and Quality Characteristics of Fresh Wet Noodles.

Jun-Jie Xing,Ke-Xue Zhu,Xiao-Na Guo,Dong-Hui Jiang,Zhen Yang

doi:10.3390/foods10040844

Jun-Jie Xing, Ke-Xue Zhu + Show 3 more

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https://doi.org/10.3390/foods10040844

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Abstract

Humidity-controlled dehydration (HCD) was innovatively applied in this paper to control the growth of microorganisms in fresh wet noodles (FWN). Effects of HCD treatment with different temperatures (40, 60 or 80 °C), relative humidity (RH, 50%, 70% or 90%) and treatment time (5–32 min) on the total plate count (TPC), the shelf-life, and qualities of FWN were investigated. The results showed that HCD reduced the initial microbial load on the fresh noodles and extended the shelf-life up to 14–15 days under refrigeration temperature (10 °C). A 1.39 log10 CFU/g reduction for the initial TPC was achieved after HCD treatment at the temperature of 60 °C and RH of 90%. HCD with higher RH had a more positive influence on quality improvement. The L* values, the apparent stickiness, and the cooking properties of the noodle body were improved by HCD while good sensory and texture quality of noodles were still maintained after the dehydration process.

Highlights

Foods 2021, 10, 844. https://doi.org/Fresh wet noodles (FWN) are prone to be contaminated by microorganisms in production and distribution due to the high-water activity and rich nutrient content [1,2].the pasteurization of fresh noodles is always a key step to be assured in the industrial production of this traditional staple food, and it is of great importance to effectively extend the shelf-life of noodle products without decreasing their edible quality [3]
The relative humidity (RH) and Humidity-controlled dehydration (HCD) time would depend on each other, since, at higher RH, the time needed to dry the product is longer due to the lower moisture gradient between product and air. This result indicated that HCD could inhibit the growth of microbes to a certain degree, and it had a more positive effect under the condition of either higher RH and temperatures, or longer HCD time
The initial total plate count (TPC) of 40 ◦ C-70%, 60 ◦ C-70% and 80 ◦ C-70% samples were lower than that of the control by 0.37, 0.85, 1.54 log10 CFU/g, respectively, and a maximum inactivation level of 1.94 log10 CFU/g for the initial TPC of the HCD noodles was achieved in this study under the conditions of 80 ◦ C-90%

Summary

Introduction

Fresh wet noodles (FWN) are prone to be contaminated by microorganisms in production and distribution due to the high-water activity and rich nutrient content [1,2]. The pasteurization of fresh noodles is always a key step to be assured in the industrial production of this traditional staple food, and it is of great importance to effectively extend the shelf-life of noodle products without decreasing their edible quality [3]. Decreasing pH by the addition of organic acid into fresh noodles had been proven to be an effective preservation method [7], while directly adding into or spraying edible alcohol on the surface of the noodles is currently the most widely used method for pasteurization during the fresh noodle production [8]. By adding a variety of natural and/or chemical preservatives, like sodium/calcium propionate, capryl monoglyceride, tea polyphenols, or chitosan into the noodle bodies, better antimicrobial and fresh-keeping results have been achieved in practice [5,9]

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