Table 2. A summary of studies to overcome the cheese processing from camel milk (CM) by altering the milk composition and optimize the processing conditions.

No.	Type of cheese produced	Objective of study	Fortification of CM with other milks or non-milk ingredients	Processing condition	Results/findings	References
Comparing the effect of milk composition (CM vs other milks) on cheese production and quality attributes.
1	Soft cheese	To study the chemical properties of cheese made from CM or a mixture of CM and sheep milk.	T1: 100% CM. T2: 75% CM and 25% sheep milk. T3: 75% sheep milk and 25% CM. T4: 50% CM and 50% sheep milk. T5: 100% sheep milk.	Pasteurization at 71°C, for 30 s. Trypsin enzyme (0.5 g), in 5 kg milk. CaCl2 (0.5 g), in 5 kg milk.	Total solid, protein and fat percentage was improved by increasing the amount of sheep milk. Quality attributes of cheese were also improved by mixing the sheep milk into CM.	(Saadi et al., 2019)
2	Low fat Akawi cheese	To assess the in vitro biological activities and protein degradation of low fat Akawi cheese produced from camel and bovine milk.	Bovine milk 100%. CM 15% and bovine milk 85%. CM 30% and bovine milk 70%.	Pasteurized CM and BM obtained from market. Use camel derived chymosin. Add starter culture 0.5 g/vat. Incubation at 42°C for 60 min.	Cheese produced from camel and bovine milk blends have superior functional properties in comparison to the bovine milk cheese.	(Ayyash et al., 2021)
3	White brined cheese	To determine the clotting behavior of CM with that of cow milk.	Natural composition after skimming.	Addition of sodium azide (0.02%), starter culture (3%). Chymosin (55 IMCU/L) and allowed for coagulation up to 2 h.	The sensory attributes (color and texture) was higher in cow cheese, however, panelist preferred CM cheese.	(Bouazizi et al., 2021)
4	Cheddar cheese sauce	Evaluate the effect of CM powder supplementation (5%–15%) on the quality of bovine milk cheddar cheese sauce.	Adding CM power (5%–15%) to the bovine milk.	Cheddar cheese sauce was prepared by mixing hot water with disodium phosphate, sodium citrate, chopped cheese with or without CM powder replacement (5%, 10%, and 15%).	The textural properties of final product were improved by increasing the ratio of CM powder in the blend used for cheese preparation.	(Desouky et al., 2019)
5	Soft cheese	To assess the impact of adding milky component (BMR) and sweet potato powder (SPP) on quality characteristics of cheese.	Mixing BMR (20% or 30%). Mixing SPP (1%, 2%, or 3%).	CM supplementation with BMR (20% or 30%) and SPP (1%, 2%, or 3%). Heating (65°C, 30 min) and cooling to (42°C). Addition of calcium chloride (0.04%) and sodium chloride (3%). Add yogurt culture (1%) and incubated at (42°C for 30 min). Addition of bovine pepsin (4 mg/100 g). Packing in brine solution and stored at 5°C.	Clotting time was reduced in response to BMR and SPP addition. Improved physicochemical properties of final product. pH and syneresis were decrease significantly.	(Elnemr et al., 2020)
Optimization of processing conditions
6	Soft cheese	To examined the effect of ultrafiltration and supplementation of allium roseum on CM cheese.	CM fortified with allium roseum powder and using two fat combination (full fat and skim milk) along with ultrafiltration processing.	Ultrafiltration and pasteurization at (90°C for 10 min) than cooling at (45°C). Adding CaCl2 (0.2 g/L), starter culture (1%) and camel derived chymosin. Allowed for coagulation and addition of allium. Roseum.	Ultrafiltration improved the texture attributes, enhanced fat and protein availability in cheese. The cheese obtained from allium roseum blend have higher antioxidant activities.	(El Hatmi et al., 2020)
7	Soft un-ripened cheese	To analyze the clotting behavior of CM and BM in response to acetic acid, citric acid and chymosin enzyme.	CM was supplemented with organic acid (citric acid or acetic acid). Also add CaCl2 (3%) for curd production.	Pasteurization at (63°C, 30 min), cooling (40°C). Mixing CaCl2 (3%), starter culture (3%). Addition of chymosin (50 IU/L), coagulation time (8 h).	The camel chymosin and acid coagulation induce positive impact on quality attributes of CM cheese in comparison to the cheese obtained from BM.	(Mbye et al., 2020)
8	Soft-brined cheese	To assess the impact of storage temperature on physicochemical, structural and sensory characteristics of camel and bovine cheese.	The natural composition of cow and CM.	Pasteurization (63°C for 30 min) and cooling at (35°C). Addition of CaCl2 (0.02%), starter culture (75 U/L) and camel chymosin (55 IMCU/L). Allowed for coagulation up to (2 h). Addition of NaCl (2%) and store at 10°C–15°C.	The hardness value of camel and cow cheeses were improved at 15°C ripening condition. The panelist suggested that the appropriate ripening condition for camel cheese is 10°C.	(Felfoul et al., 2021)
9	Not specified	To determine the impact of pre-heating conditions and salt addition on rheological properties of camel and bovine milk cheeses.	The natural composition of cow and CM.	Pre-heating at (50°C or 70°C for 10 min), cooling at (36°C for 5 min). Adding 10 or 20 mM CaCl2 or Na2HPO4 · 2H2O (hydrogen phosphate dehydrate). Addition of rennet (6.25 μL) in 25 mL of milk.	Pre-heating of CM at 50°C or 70°C negatively affect the gel formation, in comparison to the BM. However, addition of CaCl2 enhance gel firmness and reduce gelation time. Addition of Na2HPO4 · 2H2O produced week gel or even no gel formation.	(Kamal et al., 2017)
10	Not specified	To identify the optimum processing conditions for clotting of CM with the addition of Moringa oleifera enzyme extract.	The natural composition of cow and CM.	Pasteurization at (55°C, 60°C, and 65°C). pH ranges (4.5, 5, and 5.5). Addition of CaCl2 (0.15 g/L), and various volume of partially purified. Moringa oleifera (0%, 10%, 20%, 30%, and 40%) in 10 mL of milk.	The clotting activity was improved at pH 5 alongside pasteurization at 65°C and 10% purified extract of Moringa oleifera.	(Terefe et al., 2017)
Effect of coagulating ingredients (enzymes, acid and starter culture)
11	Fresh CM cheese	To determine the clotting behavior of CM in response to the Withania coagulant, camel chymosin or mixture of both enzymes.	Natural composition without any alteration.	Pasteurization (65°C, 30 min), cooling (40°C). Addition of 270 mmol CaCl2/L. addition of starter culture 3%. Add chymosin (50 IMCU/L) and allow for coagulation up to (8 h).	The quality attributes of cheese was improved by using mixture of withania coagulant and enzyme.	(Mbye et al., 2021)
12	White soft cheese	To evaluate the clotting behavior of CM in response to recombinant camel chymosin with or without starter culture.	Natural composition without any alteration.	Pasteurization (63°C, 30 min), cooling (35°C), Addition of CaCl2 (0.02%) and starter culture (0% or 0.5%. Addition of chymosin (CHY-Max M 2,500, 50 IMCU/L) and allow for coagulation at 37°C for 110 min. Addition of salt (1%) and stored at refrigeration temperature.	Application of recombinant camel chymosin and thermophilic starter culture significantly enhance the yield and quality characteristics of CM cheese.	(Al-Zoreky and Almathen, 2021)
13	Not mentioned	To assess the CM clotting efficiency by using chymosin, kiwi, ginger and pineapple extract during cheese making.	Natural composition without any alteration.	Pasteurization (65°C, 30 min), cooling (40°C). Addition of starter culture and enzyme (10%), and allow for coagulation.	Kiwi enzyme extract showed the highest clotting efficiency in comparison to other extract used for cheese preparation.	(Fguiri et al., 2021)
14	Soft cheese	To evaluate the coagulating effects of various level of lemon juice on CM cheese.	Natural composition without any alteration.	Tests were performed with different volumes of lemon juice (150, 200, 250, 300, 350, 400, 450, and 500 mL) and allow for coagulation at ambient temperature for 34 h.	The optimum cheese yield was obtained by using lemon juice 500 mL/2L of CM. However, the cheese has higher moisture content and soft texture with fatty appearance. Overall the acceptability were improved with the addition of lemon juice.	(Mihretie et al., 2018)