Development of a Flavored Jelly Incorporated with Green Tea Extract

Abstract

Tea (Camelia sinensis) is considered as one of the most popular non-alcoholic, non-carbonated beverage all over the world. It is rich with phenolic compounds, which have more health benefits. Green tea showed a higher polyphenol content than black tea (Anesini et al., 2008). A cup of green tea (2.5 g of green tea leaves/200 ml water) may contain 90 mg of Epigallocatechin Gallate (Cabrera et al., 2006). At present, only 21% of the world tea market belongs to Sri Lanka however Sri Lankan tea industry produces 40 – 45 % of value added tea products from the total tea exports (Herath and Silva, 2011). Development of ready-to-use product by incorporating tea creates an additional value to the primary product of tea and it will attract more consumers towards. The objectives of this study were to develop a ready to serve jelly by incorporating green tea extract, and to determine total amount of polyphenol in the product, appropriate proportion of the ingredients, and the shelf life of the product.

Methodology

The research was conducted as three experiments. In experiment 1, the suitable jelling time and temperature combination were identified. The formulated sample was subjected for three levels of time and temperature combinations. To obtain proper texture for setting of green tea jelly, the mixture was heated up to the range of 100 – 110 C for about 5 to 10 minutes.

In experiment 2, by changing the green tea extract level (0, 1, 2 and 3%), suitable amount that should be incorporated to the product was identified by seven trained evaluators. Their responses were obtained under taste, aroma, texture, color and overall acceptability parameters. Pectin, sugar, water, permitted chemicals (citric acid, ascorbic acid, sodium benzoate) and green tea extract were used as the main ingredients.

In the third experiment, Apple flavor was used and by changing the flavor strength, the suitable flavor level for the product was identified. The developed flavored jelly was evaluated for taste, aroma, mouth feel and overall acceptability, using thirty non-trained evaluators. The data of the both sensory evaluations were collected through sensory ballots and their responses were obtained in five point hedonic scale.

Identification of yeast and moulds, E’coli / Coliform and aerobic plate count were done in order to evaluate quality of the product and determine the shelf life of the final product samples during ten weeks of storage period under both ambient and refrigerator conditions. The media solutions were prepared according to the Sri Lankan Standards 516 in 1991. Changes in pH value and dissolved solid content of final product were determined to identify the stability of the product.

As the chemical requirements of the jelly, determination of moisture, acid insoluble ash and pectin content were carried out according to the Sri Lankan Standards 585: part 5 in 1994. The polyphenol content was determined by following ISO 14502-1:2005. The cost analysis of the product was calculated by considering the expenses made for the ingredients and packing materials.

The data were analyzed by Kruskal-Wallis test (non parametric) with 95 % confidence level. To select the best treatment combination, mean separation was done by Conover-Inman method (Conover, 1999). Results were analyzed through MINITAB 15 and graphical methods were used to interpret the results.