Annals. Food Science and Technology 2016 Available on-line at www.afst.valahia.ro Volume 17, Issue 2, 2016 317 STUDIES ON THE USE OF CHEMICAL PRESERVATIVES IN THE PRESERVATION OF ROSELLE DRINK AND PINEAPPLE FLAVOURED ROSELLE DRINK CONCENTRATES Gbadegesin Adewumi Ronke 1* and Odunlade Tunji Victor 1 1 Department of Food Science and Technology, Obafemi Awolowo University, Ile-Ife, Nigeria Email: ronkeadewumi@gmail.com Abstract Roselle drink concentrate and pineapple flavoured roselle drink concentrates were produced through the reduction of water used for extraction. This was with the additional intent of evaluating the effects of chemical preservatives (0.1% sodium benzoate and 0.01% ethylenediaminetetraacetic acid (EDTA)) on the elongation of the shelf life of roselle drink concentrate and pineapple flavoured roselle drink concentrates. These effects were investigated by determining the pH, titratable acidity (% malic acid), total soluble solids, colour intensity, vitamin C content and the sensory evaluation of the samples weekly during storage at ambient temperature for 4 weeks. Microbial analyses were also carried out on the samples before and after 4 weeks of storage. The results showed that the range of values for pH, titratable acidity, total soluble solids, colour intensity and vitamin C for all the samples were between 1.81 to 2.12, 1.26 to 1.50% malic acid, 18.60 to 23.50 ºBrix, 2.160 to 2.224 and 32.09 to 37.24 mg/100 g, respectively. There was no detectable microbial growth in any of the samples before and after storage. The sensory properties of the samples were kept throughout the storage period. The study recommends the combinatorial usage of sodium benzoate (0.1%) and EDTA (0.01%) to extend the shelf life of roselle drink and pineapple flavoured roselle drink concentrates. Keywords: Hibiscus sabdariffa, Ananas comosus, vitamin C, pH, total soluble solids Submitted: 25.05.2016 Reviewed: 15.07.2016 Accepted: 02.09.2016 1. INTRODUCTION Roselle, also known as Sorrel or Jamaica flower, has been expended by people for preparing soft drinks and in traditional medicine (Juliani et al., 2009). The word zobo is derived from zoborodo, a northern Nigerian (Hausa) name for roselle plant (Mukhtar, 2007). Roselle drink is an aqueous extract of Hibiscus sabdariffa calyces and is a non- alcoholic beverage made from the reddish purple dried calyces. It has been proven to reduce blood pressure and cholesterol levels (Olajide, 2012). The drink is a good source of ascorbic acid and minerals such as calcium, iron and phosphorous (Mohamed et al., 2007). It has been shown to possess medicinal properties including antiseptic, diuretic, antioxidant, anti-diabetic, anti-hypertensive and anti-inflammatory properties (Osueke and Ehirim, 2004). Economically, it is cheaper when compared with other available soft drinks. In spite of the nutritional, medical and economic benefits of this dink, its greatest limitation is that it deteriorates rapidly. It has a very short life of 24 h if not refrigerated (Omemu et al., 2006). It contains microorganisms which can cause food spoilage (Omemu et al., 2006). Roselle drink is often contaminated with enteropathogenic microorganisms with as much as 2.49 x 10 4 cfu/ml, which could be harmful to persons who consume large quantities of the drink (Bukar et al., 2009). Major points of contamination of the drink includes; the packaging material, as most retailers package the drink in already used plastic bottles and polyethene bags, which are not properly disinfected prior to packaging (Nwafor and Ikenebomeh, 2009a). The dried calyces are also a major point of contamination as they harbor spoilage organisms such as Penicillium and Aspergillus spp. (Amusa et al., 2005) and the retailers, who seldomly prepare the drink under aseptic conditions and often do not do enough boiling to reduce the microbial load in the preparation of the beverage. Pineapple is known for its attractive flavour. Sucrose is a sweetener and can also act as a  2016 Valahia University Press Further reproduction without permission is prohibited