Protein substitution to produce a processed cheese with high branched-chain amino acids of medical and genetic importance

ABSTRACT

The most important metabolic impairment in patients with advanced liver disease is characterized by low levels of circulating branched chain amino acids [BCAAs]. The etiology of such abnormal amino acid metabolism is multifactorial including protein restricted diet or inadequate nutritional intake as in protein energy malnutrition. Multiple studies report the beneficial effects of BCAAs supplementation to improve plasma amino acids imbalance, several neurologic diseases, protein energy malnutrition, and subsequently the survival rate of cirrhotic patients. In the present study we used a protein substitution technique to synthesize a new processed cheese as a dairy source rich in BCAAs, with low phenylalanine content manufactured from Ras cheese, kariesh cheese, butter oil and phenylalanine-free milk. Chemical composition, amino acids analysis, rheological properties and sensory evaluation were done to all of the cheese samples. L-Phenylalanine was selected to induce hepatic and brain affections in Begg Albino strain c [BALB/c] mice model. Effect of 2.5%, 5% and 10% protein-replacement cheese formulas was evaluated among mice groups including histopathological sections of the liver and brain; colorimetric determination for liver enzymes; serum total and differential cholesterol profile, serum albumin, globulin and total protein along with phenylalanine levels determinations. Analysis of the processed cheese sample with 10% protein substitution revealed that the protein content was 7.42 mg/g [about 50% of the content in the standard processed cheese] while fat content, acidity and moisture were nearly the same. The sensory score for all the formulas ranged from 79-88. Highest content of BCAAs along with least phenylalanine content was attained in the processed cheese with 10% protein substitution. Weight of mice fed on different substitution formulas ranged from 22.8 +/- 2.2-24.66 +/- 2.5 g compared with 17.8 +/- 1.9 g in the untreated diseased mice [P< 0.05]. Serum phenylalanine was 1.822 +/- 0.42 mg/dl in the mice fed on 10% protein substitution formula compared to 6.2 +/- 1.32 mg/dl in the untreated mice [P < 0.01]. There was a highly significant difference [P <0.01] between untreated mice and mice fed on 10% substitution cheese formula as regards the serum protein, Aspartate Transaminase [AST] and Alanine Transaminase [ALT]. The improvement in histopathological findings was more apparent in the mice fed on 10% formula cheese. The manufactured processed cheese with 10% protein substitution was proved to have a more nutritional therapeutic potential that can help in the implementation of dietary management in many medical and genetic disorders with liver and brain affections