Acta Scientiarum Polonorum Technologia Alimentaria

Background. Plant-based additives are increasingly used in the dairy industry for their functional and nutri­tional benefits. Incorporating plant residues or by-products into dairy products such as cheese, yoghurt and Labneh can enhance their nutritional value. This study aimed to improve the nutritional properties of Karish cheese by fortifying it with plant sources such as guava and lemon leaves, which are rich in vitamins, and essential minerals.
Materials and methods. Fresh guava and lemon leaves were added to Karish cheese at concentrations of 0.25%, 0.50% and 0.75%. The physicochemical, microbiological, rheological, antioxidant, and organoleptic properties, as well as bioactive compounds (total phenolic and total flavonoid content), were assessed during storage at 5 ±1°C for 21 days. Nutritional content, including selected minerals and vitamins, was evaluated in fresh samples.
Results. The addition of guava and lemon leaves significantly affected the moisture, protein, SN, ash, acidity and pH of Karish cheese. Fortified samples exhibited elevated levels of essential minerals (Ca, Fe, Mg, P, K and Zn) and vitamins (B1, B2, B3, B6, A, C and E). Cheeses enriched with guava leaves showed significantly higher (p ≤ 0.05) antioxidant activity, total phenols, and flavonoid contents than those with lemon leaves. Total bacterial counts were higher in the fortified treatments compared to the control, but coliforms were un­detectable across all treatments throughout storage. Texture profile analysis revealed significant increases (p ≤ 0.05) in hardness, cohesiveness, gumminess, and chewiness and decreases in adhesiveness and springiness. All cheese treatments were found to be organoleptically acceptable, with the highest overall acceptability recorded for cheese fortified with 0.25% guava and lemon leaves.
Conclusion. Fresh guava and lemon leaves can be effectively used to fortify Karish cheese at levels up to 0.75%, enhancing its nutritional, functional and sensory qualities without compromising overall acceptability.