Dietary inclusion of enzyme- or probiotic-treated date palm leaves enhances the textural and sensory properties of cheese produced from sheep milk

Abstract

This study evaluated the effects of including date palm leaves (DPL) in the diets of lactating Farafra ewes on milk yield, fatty acid composition, and the quality of white soft cheese produced from their milk. The leaves were ensiled either untreated, with fibrolytic enzymes (ENZ), or with multi-species probiotics (MSP). Diets included DPL at 50% or 100% of the forage portion. Ensiling DPL with ENZ or MSP significantly increased milk yield (linear effect, p < 0.01) and enhanced milk components, including total solids, fat, lactose, and energy content (p < 0.001), with MSP diets producing higher solids-not-fat and lactose (p < 0.001) than ENZ. Both treatments improved milk fatty acid profiles by increasing polyunsaturated and conjugated linoleic acids and elevating the unsaturated-to-saturated fatty acid ratio, while reducing the atherogenicity index (p < 0.001). Cheese produced from milk of ewes fed treated DPL exhibited signs of accelerated ripening during 28 days of storage, as evidenced by increased titratable acidity, soluble nitrogen, and total volatile fatty acids, along with decreased pH. Moisture decreased significantly (p < 0.001), whereas acidity increased markedly (p < 0.001) during storage across all treatments, and total volatile fatty acids also increased (p < 0.001), reaching the highest values in MSP100 cheeses at the end of storage. Total and soluble nitrogen contents also increased over storage (p < 0.001), indicating enhanced proteolysis. Sensory scores for flavor, texture, and appearance improved significantly in ENZ and MSP groups (p ≤ 0.011), with higher overall acceptability observed in ENZ50 cheese, followed by MSP50 (p < 0.001). Textural analysis showed marked increases in hardness, cohesiveness, springiness, gumminess, and chewiness during storage (p < 0.001). Cheeses from the MSP50 group exhibited superior texture attributes, including hardness, cohesiveness, gumminess, and chewiness values compared to other treatments (p < 0.01). The interaction between treatment and storage time was significant for most parameters (p < 0.01), confirming the dynamic influence of diet and ripening duration. In conclusion, feeding lactating ewes with DPL ensiled with fibrolytic enzymes or MSP improved milk yield, fatty acid composition, and the sensory and textural qualities of white soft cheese. The results highlight treated DPL as a promising feed option for sustainable dairy production.

Keywords

date palm leaves / white soft cheese / fibrolytic enzymes / multi-species probiotics / cheese texture / cheese ripening

References

[1] Kholif AE, Hamdon HA, Gouda GA, et al. (2022) Feeding date-palm leaves ensiled with fibrolytic enzymes or multi-species probiotics to Farafra ewes: intake, digestibility, ruminal fermentation, blood chemistry, milk production and milk fatty acid profile. Animals 12: 1107. https://doi.org/10.3390/ani12091107

[2] Gouda GA, Kholif AE, Hamdon HA, et al. (2022) Utilization of waste date palm leaves biomass ensiled with malic or lactic acids in diets of Farafra ewes under tropical conditions. Animals 12: 1432. https://doi.org/10.3390/ani12111432

[3] Kholif AE, Olafadehan OA, Anele UY (2026) Utilization of date palm leaves for livestock feed, In: Maqsood S, Roobab U, Aadil RM (Eds.), Sustainable Valorization of Date Palm By-products and Wastes, Elsevier, 185-206. https://doi.org/10.1016/B978-0-443-29023-7.00010-0

[4] Hamdon HA, Kassab AY, Vargas-Bello-Pérez E, et al. (2022) Using probiotics to improve the utilization of chopped dried date palm leaves as a feed in diets of growing Farafra lambs. Front Vet Sci 9: 1048409. https://doi.org/10.3389/fvets.2022.1048409

[5] Kholif AE, Patra AK (2024) Dietary applications of exogenous enzymes to improve nutrient utilization and performance in ruminants, In: Mahesh MS, Yata VK (Eds.), Feed Additives and Supplements for Ruminants, Singapore, Springer Nature Singapore, 1-28. https://doi.org/10.1007/978-981-97-0794-2_1

[6] Saleem ASA, Abdelnour S, Bassiony SM, et al. (2025) Probiotic supplementation in sustainable sheep production: impacts on health, performance, and methane mitigation. Trop Anim Health Prod 57: 1-22. https://doi.org/10.1007/s11250-025-04439-y

[7] Arda B, Akdeniz V, Kara HH, et al. (2025) Fatty acid profile, conjugated linoleic acid (CLA) content, microbiological and sensory properties of kefir produced from sheep milk using kefir grains and starter culture in comparison with the respective kefir from cow milk. Int Dairy J 162: 106157. https://doi.org/10.1016/j.idairyj.2024.106157

[8] Di Paolo M, Vuoso V, Ambrosio RL, et al. (2023) Role of feeding and novel ripening system to enhance the quality and production sustainability of curd buffalo cheeses. Foods 12: 704. https://doi.org/10.3390/foods12040704

[9] Ioannidou MD, Maggira M, Samouris G (2022) Physicochemical characteristics, fatty acids profile and lipid oxidation during ripening of graviera cheese produced with raw and pasteurized milk. Foods 11: 2138. https://doi.org/10.3390/foods11142138

[10] Kholif AMM, Kholif AE (2025) Organic acid-treated ensiled date palm leaves improve texture and sensory quality of white soft cheese from Farafra sheep milk in arid environments. Biocatal Agric Biotechnol 69: 103798. https://doi.org/10.1016/j.bcab.2025.103798

[11] NRC (2007) Nutrient requirements of small ruminants: Sheep, goats, cervids, and new world camelids, Washington DC, National Academies Press.

[12] Ulbricht TLV, Southgate DAT (1991) Coronary heart disease: Seven dietary factors. The Lancet 338: 985-992. https://doi.org/10.1016/0140-6736(91)91846-M

[13] Tyrrell HF, Reid JT (1965) Prediction of the energy value of cow’s milk. J Dairy Sci 48: 1215-1223. https://doi.org/10.3168/jds.S0022-0302(65)88430-2

[14] AOAC (2019) Official Methods of Analysis of AOAC International, Washington DC, Oxford University Press.

[15] Kosikowski F V . (1982) Cheese and fermented milk foods, Brooktonale, New York, F. V. Kosikowski and Associates.

[16] Clark S, Costello M, Drake MA, et al. (2009) The sensory evaluation of dairy products, New York, NY, Springer US. https://doi.org/10.1007/978-0-387-77408-4

[17] Glibowski P, Zarzycki P, Krzepkowska M (2008) The rheological and instrumental textural properties of selected table fats. Int J Food Prop 11: 678-686. https://doi.org/10.1080/10942910701622599

[18] Anee IJ, Alam S, Begum RA, et al. (2021) The role of probiotics on animal health and nutrition. The Journal of Basic and Applied Zoology 82: 52. https://doi.org/10.1186/s41936-021-00250-x

[19] Kholif AE, Anele A, Anele UY (2024) Microbial feed additives in ruminant feeding. AIMS Microbiol 10: 542-571. https://doi.org/10.3934/microbiol.2024026

[20] Rigout S, Hurtaud C, Lemoscjuet S, et al. (2003) Lactational effect of propionic acid and duodenal glucose in cows. J Dairy Sci 86: 243-253. https://doi.org/10.3168/jds.S0022-0302(03)73603-0

[21] Kholif AE, Olafadehan OA (2022) Dietary strategies to enrich milk with healthy fatty acids-A review. Ann Anim Sci 22: 523-536. https://doi.org/10.2478/aoas-2021-0058

[22] Corl BA, Baumgard LH, Dwyer DA, et al. (2001) The role of Δ9-desaturase in the production of cis-9, trans-11 CLA. J Nutr Biochem 12: 622-630. https://doi.org/10.1016/S0955-2863(01)00180-2

[23] Moreira RV, Costa MP, Frasao BS, et al. (2020) Effect of ripening time on bacteriological and physicochemical goat milk cheese characteristics. Food Sci Biotechnol 29: 459-467. https://doi.org/10.1007/s10068-019-00682-w

[24] Nájera AI, Nieto S, Barron LJR, et al. (2021) A review of the preservation of hard and semi-hard cheeses: quality and safety. Int J Environ Res Public Health 18: 9789. https://doi.org/10.3390/ijerph18189789

[25] Zheng X, Shi X, Wang B (2021) A review on the general cheese processing technology, flavor biochemical pathways and the influence of yeasts in cheese. Front Microbiol 12: 703284. https://doi.org/10.3389/fmicb.2021.703284

[26] Rilla N, Martínez B, Delgado T, et al. (2003) Inhibition of Clostridium tyrobutyricum in Vidiago cheese by Lactococcus lactis ssp. lactis IPLA 729, a nisin Z producer. Int J Food Microbiol 85: 23-33. https://doi.org/10.1016/S0168-1605(02)00478-6

[27] Coelho MC, Malcata FX, Silva CCG (2022) Lactic acid bacteria in raw-milk cheeses: From starter cultures to probiotic functions. Foods 11: 2276. https://doi.org/10.3390/foods11152276

[28] Bansal V, Veena N (2022) Understanding the role of pH in cheese manufacturing: general aspects of cheese quality and safety. J Food Sci Technol 61: 16-26. https://doi.org/10.1007/s13197-022-05631-w

[29] Estrada O, Ariño A, Juan T (2019) Salt distribution in raw sheep milk cheese during ripening and the effect on proteolysis and lipolysis. Foods 8: 100. https://doi.org/10.3390/foods8030100

[30] Zhao X, Zheng Z, Zhang J, et al. (2019) Change of proteolysis and sensory profile during ripening of Cheddar-style cheese as influenced by a microbial rennet from rice wine. Food Sci Nutr 7: 1540. https://doi.org/10.1002/fsn3.1003

[31] Tavaria FK, Franco I, Carballo FJ, et al. (2003) Amino acid and soluble nitrogen evolution throughout ripening of Serra da Estrela cheese. Int Dairy J 13: 537-545. https://doi.org/10.1016/S0958-6946(03)00060-8

[32] You L-Q, Wang Y-R, Bai S, et al. (2024) Impact of ripening periods on the key volatile compounds of Cheddar cheese evaluated by sensory evaluation, instrumental analysis and chemometrics method. Appl Food Res 4: 100578. https://doi.org/10.1016/j.afres.2024.100578

[33] Sant’Ana AMS, Bessa RJB, Alves SP, et al. (2019) Fatty acid, volatile and sensory profiles of milk and cheese from goats raised on native semiarid pasture or in confinement. Int Dairy J 91: 147-154. https://doi.org/10.1016/j.idairyj.2018.09.008

[34] Falih MA, Altemimi AB, Hamed Alkaisy Q, et al. (2024) Enhancing safety and quality in the global cheese industry: A review of innovative preservation techniques. Heliyon 10: e40459. https://doi.org/10.1016/j.heliyon.2024.e40459

[35] Maqsood S,Adiamo O,Ahmad M, et al. (2020) Bioactive compounds from date fruit and seed as potential nutraceutical and functional food ingredients. Food Chem 308: 125522. https://doi.org/10.1016/j.foodchem.2019.125522

[36] Ianni A, Bennato F, Martino C, et al. (2020) Volatile flavor compounds in cheese as affected by ruminant diet. Molecules 25: 461. https://doi.org/10.3390/molecules25030461

[37] Gulati A, Galvin N, Hennessy D, et al. (2018) Grazing of dairy cows on pasture versus indoor feeding on total mixed ration: Effects on low-moisture part-skim Mozzarella cheese yield and quality characteristics in mid and late lactation. J Dairy Sci 101: 8737-8756. https://doi.org/10.3168/jds.2018-14566

[38] Lamichhane P, Kelly AL, Sheehan JJ (2018) Symposium review: Structure-function relationships in cheese. J Dairy Sci 101: 2692-2709. https://doi.org/10.3168/jds.2017-13386

[39] D’Incecco P, Limbo S, Hogenboom J, et al. (2020) Impact of extending hard-cheese ripening: A multiparameter characterization of Parmigiano Reggiano cheese ripened up to 50 months. Foods 9: 268. https://doi.org/10.3390/foods9030268

[40] Wang W,Jia R,Hui Y, et al. (2023) Utilization of two plant polysaccharides to improve fresh goat milk cheese: Texture, rheological properties, and microstructure characterization. J Dairy Sci 106: 3900-3917. https://doi.org/10.3168/jds.2022-22195

[41] Tsioulpas A, Lewis MJ, Grandison AS (2007) Effect of minerals on casein micelle stability of cows’ milk. J Dairy Res 74: 167-173. https://doi.org/10.1017/S0022029906002330

[42] Moss R, Le Blanc J, Gorman M, et al. (2023) A prospective review of the sensory properties of plant-based dairy and meat alternatives with a focus on texture. Foods 12: 1709. https://doi.org/10.3390/foods12081709