Vol. 8(26), pp. 1212-1218, 11 July, 2013 DOI 10.5897/SRE12.492 ISSN 1992-2248 © 2013 Academic Journals http://www.academicjournals.org/SRE Scientific Research and Essays Full Length Research Paper Chemical stability of vacuum packaged West African cheese (Wagashie) Sulley Addo Tohibu, Emmanuel Amankwah and Ibok Oduro* Department of Food Science and Technology, KNUST, Kumasi, Ghana. Accepted 31 May, 2013 Local West African cheese (Wagashie) samples from unpasteurized full-fat milk (UFFM), pasteurized full-fat milk (PFFM) and partially pasteurized skimmed milk (PPSM) were prepared and a fourth (control) was purchased from a local commercial producer. The study was to determine chemical changes of the Wagashie samples over a four week storage period. All the four Wagashie samples were vacuum- packaged at pressure of 11.1 bars and stored at 12°C. Chemical tests (moisture, crude proteins, fat, free fatty acid and pH) were conducted on week zero, one, two and four. Percent moisture (wet basis) and FFA, after the storage period, reduced and increased (p< 0.05) respectively. Percent protein (wet basis) remained unchanged (p> 0.05) in samples PPSM and PFFM but increased (p< 0.05) in the other two samples. Percent fat increased in PPSM and control but decreased in the other two samples (p< 0.05). pH of all the Wagashie samples reduced (P< 0.05) at the end of storage. The study showed that the greatest change in terms of the parameters considered occurred in the control after storage. Key words: Wagashie, vacuum packaging, chemical stability. INTRODUCTION ‘ Wagashie’ is a cheese prepared from cow’s milk and patronized by people in the West African sub-region. It can be described as soft unripened cheese because of its high moisture content of about 50% wet basis (Ashaye et al., 2006) and the fact that it is not allowed to go through the ripening stage before consumption (public opinion). In preparing Wagashie cheese Calotropis procera juice extract, a milk protein coagulant, is added to warmed milk (Ogundiwin and Oke, 1983). The milk is gently stirred and the temperature increased slowly until it reaches the boiling point. At this stage a visible separation of the curds from the whey is observed. The pieces of curds are then collected into small raffia baskets that define the shape of the product; at this stage the product is called Wagashie. Wagashie is a highly perishable product. It was observed by Ashaye et al. (2006) that the shelf life does not exceed three days. After the second day of storage, Wagashie under ambient temperature undergoes considerable undesirable chemical changes. These changes (moisture change, proteolysis and lypolysis) are caused by increased activity of the resident lactic acid bacteria and adventitious microbes. The moisture content reduces causing hardening; proteolysis sets in resulting in the sourness of the product and lypolysis occurs imparting a rancid aroma to it. The change in the composition is accompanied by changes in the sensory quality of the product (Appiah, 2000). Studies have been carried out to improve upon the keeping quality of this nutritious soft cheese. In a study conducted by Appiah (2000), different concentrations of NaCl solution were applied to extend the shelf-life of Wagashie up to fifteen days. Similarly, application of preservatives like propionic acid and sodium benzoate (Joseph and Akinyosoye, 1997), biological plant extracts like Afromomum danielli (Ashaye et al., 2006), ginger and *Corresponding author. E-mail: iquomma@yahoo.com.