Effect of Processing and Storage on the Quality of Beetroot and Apple Mixed Juice.

Flavia Bianchi,Marina Pünsch,Elena Venir

doi:10.3390/foods10051052

Abstract

In recent years, there has been a growing interest in the development of health-promoting and disease-preventing functional foods. Beetroot is a promising vegetable because of its outstanding antioxidant activity, vivid colour, and content of bioactive compounds. In the present study, the quality of pure beetroot and apple juices as well as that of their mixture was evaluated by measuring changes of colour, betalain content, and antioxidant activity during processing and storage. No perceivable colour changes of the beetroot juice were observed after adding apple juice up to 85% of the total amount. However, the antioxidant activity was proportionally reduced with the addition of apple juice. Pasteurization negatively affected the content of betalains but did not influence the antioxidant activity. Storage led to colour modifications and reduction of betalains and antioxidant activity. Through preliminary shelf-life studies, a durability of 65 days at room temperature for apple and beetroot juice blends was calculated. The novelty of this study lies in an extended description of physico-chemical characteristics of a fresh apple and beetroot blended juice obtained from local products, in the study of the effects of processing and storage on its quality, and in the estimation of its shelf-life after storage at different temperatures.

Highlights

Beetroots (Beta vulgaris) are a good source of dietary fibres, minerals, vitamins, phenolics, and antioxidant compounds [1,2,3,4,5,6]
Four jars were stored at −30 ◦C until analyses, while other 66 jars were subjected to further pasteurization (PAJ) at 85 ◦C for 3 min after the temperature in the core reached 85 ◦C, in an oven with steam function (CM 61, Rational Italia S.r.l., Mestre, Italy)
Cloudy apple juice purchased on the market Apple juice (AJ) subjected to pasteurization Raw beetroot juice obtained through a household juice extractor Beetroot juice obtained by means of pilot-scale turboextractor Beetroot juice (BJ) subjected to pasteurization Blended juice obtained by diluting beetroot juice (BJ; 15%) with apple juice (AJ; 85%) Beetroot and apple juice blend subjected to pasteurization

Summary

Introduction

Beetroots (Beta vulgaris) are a good source of dietary fibres, minerals, vitamins, phenolics, and antioxidant compounds [1,2,3,4,5,6]. They have a potential relevance for human health, since they provide a high content of functional components known for their antioxidant and anti-inflammatory properties [7,8] and anticarcinogenic potential [9,10,11]. The chemical structure of betalains influence their antioxidant potential: the presence of an aromatic ring positively affects the radical scavenging activity; in betaxanthins, the antioxidant capacity depends on the number of hydroxy and imino residues, while acylation and glycosylation lead to an increased or decreased antioxidant activity of betacyanins, respectively [17].

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Conclusion