Effect of a Novel Microwave-Assisted Induction Heating (MAIH) Technology on the Quality of Prepackaged Asian Hard Clam (Meretrix lusoria).

Yi-Chen Lee,Tien-Hsiang Chang,Chung-Saint Lin,Yung-Hsiang Tsai,Tsung-Yin Ou,Wei-Han Zeng,Kuohsun Chiu,Chiu-Chu Hwang

doi:10.3390/foods10102299

Abstract

The microwave-assisted induction heating (MAIH) method—an emerging thermal technique—was studied to heat the prepackaged raw hard clam (Meretrix lusoria). The cooking effects on microbial and physiochemical qualities of clam were investigated. After the heating of the clam meat samples, the aerobic plate count (APC), psychrotrophic bacteria count (PBC), and total volatile basic nitrogen (TVBN) levels decreased with increasing heating time, but the shucking ratio, area shrinkage, and texture (hardness, cohesiveness, and chewiness) increased. In addition, the L* (lightness) and W (whiteness) of the clam meat samples increased significantly at the beginning of the heating period, whereas they decreased significantly with extended heating time. However, a* (redness) had the opposite trend. This study found that when clams were heated for more than 120 s at 130 °C or 150 s at 90 °C, they displayed obvious shrinking and a yellow-brown appearance, indicating that they are overcooked. After heating by MAIH for at least 110 s at 130 °C or 130 s at 90 °C, the samples were cooked well and gains a completely shucking, along with no microbial count detected. Therefore, the results indicated that the optimum heating conditions for prepackaged hard clams subjected to an MAIH machine were 130 °C for 110 s or 90 °C for 130 s.

Highlights

Microwave (MW) heating has some merits, such as reduced processing time, a fast heating rate, and minimized destruction of food nutrients and flavors [1]
The 10 specimens of clam were each placed in crystallized polyethylene terephthalate (CPET) containers (13 cm internal diameter × 3.0 cm height) containing 1% saline equal to the clam weight
A dark appearance was observed in the clam meat; when clams were heated for more than 120 s at 130 ◦ C

Summary

Introduction

Microwave (MW) heating has some merits, such as reduced processing time, a fast heating rate, and minimized destruction of food nutrients and flavors [1]. MW combined with other conventional heating methods can effectively overcome the drawbacks of the MW technique [7] This combination known as microwave-assisted (MA) processing technology, such as MA vacuum frying, MA oven drying, MA freeze drying, and MA steam heating, have been widely applied to food processing [7]. In MATS and MAPS, the food prepackaged in polymer containers is heated in pressurized hot water and microwave heating set at 915 MHz of frequency to perform rapid sterilization or pasteurization. The utilization of heating water as an intermediate can reduce edge heating in food packages by using MW heating [9] This process is an effective technique to eliminate microbial count, accompanied by reducing the decomposition of nutrition and flavors in soft bag food [8]. MATS has been used to study thermal treatments for various foods, including asparagus, macaroni and cheese, salmon, chicken, mashed potatoes, and sliced beef [4,8]

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