A Comparison of the Physico-Chemical and Microbiological Analyses of the Juice Obtained by Third-Year Students of the Science and Humanity School to Artisan and Industrial Juice Sold in Goma Food Stores after Six Months of Storage
Marc HYANGO ODIMBA *
Department of Biology and Chemistry, Exact Sciences Section, Nyiragongo Higher Institute, North Kivu, Democratic Republic of the Congo.
Jean-Pierre IKOLONGO BEFEMBO
Department of Chemistry, Faculty of Science and Technology, National Pedagogical University, Kinshasa, Democratic Republic of the Congo.
José INDENGE Y' ESSAMBALAKA
Department of Mathematics, Statistics and Computer Science, Faculty of Science and Technology, National Pedagogical University, Kinshasa, Democratic Republic of the Congo.
*Author to whom correspondence should be addressed.
Abstract
Fruit juice is the juice obtained from fruits by mechanical means that is fermentable but not fermented, possessing the characteristic colour, aroma and taste of the fruits from which it is derived. The objective of this study is to evaluate the physicochemical and microbiological quality after a six-month storage period at room temperature of passion fruit juice prepared by third-year scientific students from six schools in the city of Goma. Thesis results are compared with juice produced in an artisanal manner in Goma and industrial juice imported and sold in the city's shops, which generally have a shelf life exceeding 12 months. This comparison will allow us to assess the quality of juice made by students in relation to that made in an artisanal and industrial way, verifying over time whether manufacturers truly comply with the expiration date indicated on the labelling.
The results show that the juices prepared by the students and those artisanal present values that fluctuate around the standards, but with notable discrepancies in certain essential parameters such as pH, density, and viscosity. In contrast, industrial juices generally comply with AFNOR standards, reflecting the use of standardised and controlled manufacturing methods.
Microbiological analyses reveal concerning results for certain schools and the artisanal juices after six months of storage, notably the presence of coliforms and yeasts, indicating potential contamination and posing risks to consumer health. The detection of Escherichia coli in some samples indicates improper handling and storage, which could be attributed to a lack of hygiene during production. On the other hand, industrial juices after six months of storage show complete compliance with food safety standards, with no significant contamination, reflecting rigorous manufacturing practices and effective quality control. In conclusion, the results of the physicochemical and microbiological analyses highlight significant disparities between the passion fruit juices prepared by students, artisanal juices, and industrial juices.
Keywords: Passion fruit juice, food preparation, storage, time, temperature