Contribution à l’étude pour la caractérisation du fromage traditionnel « Bouhezza » au lait de chèvre.

Abstract

Bouhezza is a traditional Algerian cheese, from Chaouia terroir produced from different types of milk (goat, sheep and cow). Its manufacture refining is carried out in a skin bag prepared traditionally from goatskin or sheepskin, called Djeld or Chekoua of Bouhezza. The objective of the study was to contribute to the characterization of traditional cheese Bouhezza through a survey in different regions of Chaouia, in northeastern Algeria. A physicochemical, biochemical and microbiological characterization of Bouhezza prepared with goat’ raw milk. The survey was conducted among 617 families in urban areas and 225 in rural areas, in order to establish the production diagram of Bouhezza and delineate the geographical area of his practice. Thirteen cheese making of Bouhezza with raw goat milk were made; 2 experimental in laboratory (LNTA-I.N.A.T.A-A) - University of Constantine 1) and 11 in farms (4 in Tébessa and 7 in Oum El-Bouaghi). During ripening, physicochemical and microbiological analyzes were carried out. Determination of proteolysis during maturation, isolation and identification of proteolytic lactic acid bacteria found in the cheese were performed by SDS-PAGE electrophoresis and PCR. Peptide profile was analyzed by RP-HPLC. The evaluation of the proteolysis rate, highlighting profiles lipid by GC, and aromatic by GC-MS, with a sensory analysis and texture profile of Bouhezza cheese. The microbiological characterization of cheese with identification of lactic acid bacteria by sequencing of 16S rDNA using PCR-TTGE. The investigation confirmed the practice of Bouhezza in different regions of Chaouia in 5 wilayas; Khenchela, Batna, Tebessa, Souk Ahras and Oum El Bouaghi. Of 498 respondents, 49.76% (247) know and manufacture Bouhezza. He is also called ""Milh Dhouaba"" at Tébessa. The microbiological analysis revealed a high number of lactic acid bacteria, of the order of 7.7 to 8.9 log cfu / g of cheese, the absence of pathogenic bacteria, while the flora of contamination was present at the beginning of manufacturing, but decreased with time. Therefore, the cheese has an acceptable hygienic quality. The lactic flora showed fluctuations during manufacture with a heavy load of lactic Streptococci consisting essentially of strains of: Lc. lactis subsp. cremoris and S. gallolyticus subsp. macedonicus. Lactobacilli are present with a low charge, composed of Lb. plantarum, Lb. johnsonni, Lb. gasseri; Lb. fermentum, Lb. helveticus, Lb. acidophilus and Lb. crispatus. Bouhezza is an acidic fermented product with an average pH of 3.88 and an average acidity of 1.85 g / 100 g of lactic acid. The protein / DM level was 22.20% and the fat / DM content 41.18%. The results showed that the dry matter averaged 35.65%. The moisture content in the defatted cheese is 68.55% and 79.05%, the fat-in-dry matter of 47.65% and 34.77%. Nitrogen fractions soluble in water and in 12% TCA decreased at the beginning of the ripening process and then increased at the end of ripening. SDS-PAGE analysis on Bouhezza samples showed moderate proteolysis, from 30 days of maturation. Urea PAGE of caseins showed rapid proteolysis. Six proteolytic lactic acid bacteria (LABs), four of which have been identified by 16S rDNA sequencing, were two strains of Enterococcus faecalis, one Enterococcus faecium and one Lactobacillus paracasei ssp. paracasei. RP-HPLC analysis of the soluble fraction at pH 4.4 showed the changes that occurred during the refining process where the peptide profile confirmed proteolysis during cheese maturation. A total of more than 100 volatile compounds have been identified in goat cheese Bouhezza, the main classes of which are carboxylic acids, esters and alcohols, followed by aldehydes, ketones, terpenes and various compounds. Goat's milk cheese has been classified as ripened cheeses semi-soft to soft and semi-fat to all fat according to the codex alimentarius. Bouhezza has a good microbial diversity, which would contribute to its ripening and provide it with its organoleptic characteristics. The sensory evaluation showed that Bouhezza is salty, spicy and intense in smell and aroma. The study showed that Bouhezza cheese was rich in volatiles with a variety of odorous components that give the cheese its particularities reflecting the identity of this local cheese.