Development of a Novel Whey Date Beverage Fermented with Kefir Grains Using Response Surface Methodology

Sana M’Hir,Moktar Hamdi,Kais Rtibi,Asma Mejri,Lamia Ayed,Hajer Aloui,Manel Ziadi

doi:10.1155/2019/1218058

Abstract

The aim of this study was to develop a novel kefir beverage using date syrup, whey permeate, and whey. The levels of the kefir grain inoculum (2–5% w/v), fruit syrup (10–50% w/v), and whey permeate (0–5% w/v) on pH, total phenolic content, antioxidant activity, lactic acid bacteria and yeast counts, and overall acceptability were investigated using central composite design. The use of response surface methodology allowed us to obtain a formulation with acceptable organoleptic properties and high antioxidant activities. The obtained beverages had total phenolic content, % DPPH scavenging activity, and overall acceptability ranging from 24 to 74 mg GAE/mL, from 74.80 to 91.37 mg GAE/mL, and from 3.50 to 6 mg GAE/mL (based on a 1 to 9 preference scale), respectively. Date syrup of 36.76% (w/v), whey permeates of 2.99%, and kefir grains inoculum size of 2.08% were the optimized process conditions achieved.

Highlights

E aim of this study was to develop a novel kefir beverage using date syrup, whey permeate, and whey. e levels of the kefir grain inoculum (2–5% w/v), fruit syrup (10–50% w/v), and whey permeate (0–5% w/v) on pH, total phenolic content, antioxidant activity, lactic acid bacteria and yeast counts, and overall acceptability were investigated using central composite design. e use of response surface methodology allowed us to obtain a formulation with acceptable organoleptic properties and high antioxidant activities. e obtained beverages had total phenolic content, % DPPH scavenging activity, and overall acceptability ranging from 24 to 74 mg GAE/mL, from 74.80 to 91.37 mg GAE/mL, and from 3.50 to 6 mg GAE/mL, respectively
Results and Discussion is study was carried out to optimise the formulation of kefir-whey-date beverage with different levels of inoculum size, whey permeate (WP), and date syrup (DS) using response surface methodology (RSM) (Table 1)
Nineteen formulations of beverage were prepared, with varying kefir grain concentration from 2 to 5%, DS concentration from 1 to 50%, and WP concentration from 0 to 5% (Tables 2 and 3). e Central Point was repeated five times. e effect of these parameters was studied on pH, Lactic acid bacteria (LAB) and yeasts’ growth, DPPH radical scavenging activity (%), total phenolic content (TPC), and overall acceptability

Summary

Introduction

Roussis e aim of this study was to develop a novel kefir beverage using date syrup, whey permeate, and whey. E levels of the kefir grain inoculum (2–5% w/v), fruit syrup (10–50% w/v), and whey permeate (0–5% w/v) on pH, total phenolic content, antioxidant activity, lactic acid bacteria and yeast counts, and overall acceptability were investigated using central composite design. E use of response surface methodology allowed us to obtain a formulation with acceptable organoleptic properties and high antioxidant activities. Whey is a highly nutritious product, and it is digested and assimilated [1] It contains proteins with a very high biological value, lactose, minerals, and water-soluble vitamins [2, 3]. The hydrolysis of whey bioactive peptides such as β-lactoglobulin by probiotic bacteria is an alternative to reduce its allergenicity [23,24,25]

Methods

Results

Conclusion