Production of cheese from donkey milk as influenced by addition of transglutaminase

Abstract

Donkey milk is characterized by low contents of total solids, fat, and caseins, especially κ-casein, which results in formation of a very weak gel upon renneting. The objective of this study was to evaluate the effect of fortification of donkey milk with microbial transglutaminase (MTGase) for cheesemaking in relation to different enzyme addition protocols (patterns, PAT). Four independent trials were performed using MTGase (5.0 U/g of milk protein) according to the following experimental patterns: control (no MTGase addition); MT-Gase addition (40°C) 15 min before starter inoculation (PAT1); addition of MTGase to milk simultaneously with starter culture (40°C) (PAT2); and MTGase addition simultaneously with rennet (42°C) in acidified milk (pH 6.3) (PAT3). Evolution of pH during acidification, cheesemaking parameters, and proximal composition and color of cheese at 24 h were recorded. The protein fractions of cheese and whey were investigated by urea-PAGE and sodium dodecyl sulfate-PAGE. Addition of MTGase had no significant effect on moisture, protein, fat, or cheese yield. The addition of MTGase with rennet (PAT3) improved curd firmness compared with the control. Among the different patterns of MTGase addition, PAT3 reduced gel formation time, time between rennet addition and cheese molding, and weight loss of cheese at 24 h. The PAT3 treatment also resulted in the lowest lightness and highest yellowness color values of the cheese. Sodium dodecyl sulfate-PAGE of cheeses revealed that MTGase modified the protein pattern in the high-molecular-weight zone (range 37-75 kDa) compared with the control. Of the MTGase protocols, PAT3 showed better casein retention in cheese, as confirmed by the lanes of α-and β-caseins in the electropherogram of the whey, which was subtler for this protocol. In conclusion, MTGase may be used in cheese production from donkey milk to improve curd firmness; MTGase should be added simultaneously with the rennet.

Microbial Populations of Fresh and Cold Stored Donkey Milk by High-Throughput Sequencing Provide Indication for A Correct Management of This High-Value Product

“…Therefore, a timely treatment of the raw sample would be recommended to avoid the proliferation of an unwanted microflora, which could irreparably compromise the use of donkey milk for human consumption, and for any technological transformations. Also, in light of suggested cheese production from donkey raw milk [21,55], our findings suggested precautions to be adopted to assure the quality and the safety of these dairy products, including the possible risks associated with spontaneous fermentation [56,57].…”

Milk Products from Minor Dairy Species: A Review

“…MTGase is known to lead to the formation of a network among proteins and high molecular weight peptides, modifying the products’ protein functional properties and rheological characteristics. The results showed that the enzyme, when added simultaneously with the rennet to acidified milk (pH 6.3; 42 °C), improved the firmness of the cur, and favored the syneresis process and the retention of milk proteins [ 131 ]. From the data in Table 3 , it can be concluded that different types of rennet can be used for donkey milk cheesemaking, but the curd obtained is always weak and is only suitable for making fresh cheese.…”

Insights on Health and Food Applications of Equus asinus (Donkey) Milk Bioactive Proteins and Peptides—An Overview

“…Donkey milk is a basic ingredient for the production of high-value dairy products [89]. DM lysozyme is also used in the food industry due to its stability and resistance to various technological processes such as thermic treatment [31] and digestive tract conditions such as acid pH and gastrointestinal enzymes [90].…”

“…Because of its low fat and casein content, DM constitutes a soft gel during cheese manufacturing. Several studies have faced this situation, for example, by the addition of MTGase-a microbial transglutaminase that can enhance the texture of the curd without any effect on moisture, proteins, fats, or cheese yield [89]. Šarić et al (2016) overcame this limitation by mixing DM with goat milk to produce a functional product with high quality [94].…”