beli mesin vacuum frying

Introduction

Fried products are appreciated by all age groups and play an important role in consumer’s diet because of their unique flavor and texture. However, it is difficult to combine fried foods with the contemporary consumer trends toward healthier and low-fat products. There is an increased demand for healthy snack products with good taste, texture, and appearance . This demand offers the opportunity to design novel fried products that have higher health properties such as fruit-based products. Increasing fruit consumption is promoted in all parts of the world to increase public health. Fruit implicitly has a strong health awareness based on the content of (micro) nutrients, fibers, and numerous bioactive phytochemicals.

Vacuum frying is a frying process below atmospheric pressure (~ 100 kPa). At reduced pressure, the boiling point of oil and water is lower compared to atmospheric pressure. Due to a lower frying temperature, vacuum frying better preserves the nutritional value, aroma, and color of the fried product compared to atmospheric frying .

Some anecdotic findings from existing studies highlighted several advantages vacuum frying might have over atmospheric frying:

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Oil uptake in vacuum-fried apple chips is lower compared frying at atmospheric pressure ;

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Color of vacuum-fried mango was lighter compared to atmospheric frying ;

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Carotenoid retention was higher in vacuum-fried mango compared to atmospheric frying ;

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Vacuum-fried mango was more uniform and crispier compared to soggy, burnt, and oily for atmospheric fried mango .

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The multiple factors influencing the quality attributes of vacuum-fried fruit can be distinguished in vacuum-frying equipment (type and specifications), properties of the raw fruit (fruit matrix), pre- and post-treatments, and processing conditions. Time, temperature, and vacuum pressure influenced color, texture, nutrients, and oil content of fried fruits.

Another relevant aspect is the fruit matrix such as the fruit type and ripening stage that are affecting the vacuum-fried product quality attributes. Pre-treatments such as blanching, drying, freezing, antioxidant, and coating applications have been used to preserve color, improve texture, and reduce oil absorption. The use of post-frying steps such as centrifugation has a major effect on the oil content of fried product.

Some recent papers dealt with different aspects of vacuum-frying technology. The strategies to reduce oil absorption of vacuum-fried products have been studied intensively by Moreira, including optimizing temperature, pressure, pre-treatment, pressurization speed, and de-oiling time. The recent review by Diamante et al.  discussed the product and process optimization, oil uptake, oil quality, as well as packaging and storage of vacuum-fried fruits without mentioning matrix factors. Dueik and Bouchon and Ayustaningwarno and Ananingsih compared the quality changes comparing atmospheric and vacuum frying as well as the oil quality and packaging of fried products. Dueik and Bouchon  put emphasis on the microstructure, methods to reduce oil uptake, oil quality, bioactive compound degradation, and toxic compound generation. Andres-Bello et al.  reviewed the vacuum-frying processing for producing high-quality fried products, focusing on equipment types, pre-treatments, and vacuum-frying conditions.

Based on this existing background information, this review will consider the effects of vacuum frying on changes in quality attributes of tropical fruits with a focus on the role of the fruit matrix, since this is a very relevant but underexposed factor.