Microwave heating instead of blanching to produce low-fat French fries

Blanching pretreatment is necessary for preparing French fries, but it causes water consumption and nutrient outflow. This work was aimed to investigate the effects of microwave (MW) pretreatment instead of blanching on the quality of fries, evaluated via changes to microstructure and crust characteristics. First, MW pretreatment could inactivate polyphenol oxidase in fresh-cut potato strips to inhibit enzymatic browning. Subsequently, the fries after proper MW pretreatment (60 s) had a golden appearance and better texture. As compared with the blanching process, the oil content of the fries obtained by MW pretreatment was decreased sharply from 41.3% to 18.1%. The results of scanning electron microscopy showed that MW pretreatment significantly altered the crust and internal microstructure of fries. Specially, it was found that the MW pretreatment made the fries form a thicker protective crust (1.81 mu m), which was crucial to prevent oil adsorption during the frying and improve texture.Industrial relevance: Blanching is a traditional thermal processing technique that was once widely used in French fries around the world. However, blanching has some drawbacks, such as slow heat conduction, long processing time, substantial loss of soluble nutrients, massive water wastage, and even increased oil content of the fries. Meanwhile, MW heating is known for its high efficiency. The fries obtained with proper MW pretreatment are of good quality, but the oil content is drastically reduced compared to conventional blanching pretreatment. So, the above findings may provide helpful information to guide effective strategies for applying MW heating instead of blanching in the preparation of fried potato foods.

Automated summary

This study aimed to investigate the effects of microwave pretreatment instead of blanching on the quality of French fries. The results showed that microwave pretreatment could inhibit enzymatic browning and improve the appearance and texture of the fries. Additionally, microwave pretreatment significantly reduced the oil content and altered the microstructure of the fries.