Effects of Some Weak Acids and Moringa oleifera Leaf Extract Powder on the Colour of Dried Apple

Washiela Arendse,Victoria Jideani

doi:10.3390/pr10020206

Abstract

This study aimed to find alternatives to sulphite as a preservative for dried fruits. Granny Smith apples were sanitised in a 200 ppm sodium chlorite solution, de-cored, peeled, and cut into slices. The sliced apples were pre-treated/dipped in a water solution containing the three weak acids, namely, ascorbic acid (AA), citric acid (CA), and potassium sorbate (PS) as well as Moringa oleifera leaf extract powder (MOLEP). A screening fractional factorial experiment consisting of five independent variables (AA, CA and PS, time and temperature and MOLEP) constrained at their upper and lower levels (AA: 0.5 to 2.0%, CA: 0.3 to 2.0%, MOLEP: 0.1 to 0.2%, time: 7 to 15 h and temperature: 57 to 70 °C) were evaluated for their effect on the colour of the dried sliced apples. An increase in the concentration of the CA significantly increased the lightness (p = 0.05) and decreased the redness (p = 0.0022) of the dried apple slices. AA and PS did not impact the lightness of the dried sliced apples. A dipping solution of citric acid at 2.0%, Moringa oleifera leaf extract powder at 0.1%, and drying time of 7 h at 70 °C effectively minimized the discolouration of the dried sliced apples.

Highlights

Fruits have become a vital part of our everyday life as a result of them being an excellent source of vitamins and minerals [1]
The results indicate that run 3 with citric acid at 2.00% and the Moringa oleifera leaf extract powder (MOLEP) at 0.10% dosage had the greatest effect on the redness (2.1) and yellowness (21.3) of the dehydrated sliced apples
The hypothesis of whether the optimum combination of weak acids and Moringa oleifera leaf powder will preserve the colour of the dried apples was tested in this study

Summary

Introduction

Fruits have become a vital part of our everyday life as a result of them being an excellent source of vitamins and minerals [1]. Giving rise to a need for innovative products that can act in response to the change in lifestyle and working pace. An advantage of this is that consumers are paying attention to eating nourishing, organic, and flavoursome foods. Dehydrated fruits can fulfil these requirements as they are delicious, healthy food because of their nutritional value and high fibre content [3]. Processing fruits provide a method to make them accessible throughout the year, add value, and increase their shelf life [4]

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Results

Conclusion