Technological Valorization of Algerian Dates Downgraded from <i>Deglet Nour</i>Variety to Semi-Candied Dates in Dates Syrup

The objective of this study is the valorization of downgraded dates from a high Algerian date variety Deglet Nour, locally called “h’chef”. The work starts with the implementation of a food formulation of semi-candied dates in syrup extracted from dates. This formulation was based on dehydration-impregnation by immersion (D.I.I.). The downgraded dates were cleaned, cut, blanched, and then immersed in date syrups with increasing differential concentrations in Brix degrees: 65°, 70° and 75°. The chosen date/syrup immersion ratio is 1:2 (w/w). The obtained semi-candied dates were the subject of physicochemical and sensory analyses. The characterization of the downgraded dates before immersion showed high sugar content with a rate 52.67 g% g of dry matter and low water content (14%) which favors their use in semi-candied products. The physico-chemical analyses results of the three semi-candied dates products show an increase in their final sugar content, i.e. from 53.55% to 60.78% and in ashes between 1.76 p.cent and 1.94 p.cent. On the other hand, sensory analysis results confirm that the semi-candied dates with a syrup of 75° Brix present the most appreciated and preferable organoleptic characteristics than the other variables. Finally, following appertisation, the stability test reveals good microbiological quality (100°C for 20 minutes) of the three (3) semi-candied formulations of dates. Thus, the valorization of the “h’chef” as sorting gap Deglet Nour date allowed its transformation into semi-candied dates, stable, appreciable on the organoleptic side. This new formulation could constitute a value-added product if eventually manufactured on an industrial scale, mainly in southern Algeria.

Use of <i>Pergularia tomentosa</i>Plant Enzymatic Coagulant System in Fresh Cheese-Making

Introduction: Pergularia tomentosa is a saharan spontaneous plant belonging to Asclepiadacea family. It has several medicinal properties and uses in the human food as an auxiliary in cheese-making. The purpose of this study is the extraction of the coagulant enzymatic system (C.E.S) from the plant dried leaves and its use in the preparation of fresh cheese. Materials & Methods: The determination of the coagulant activity was carried out on a skimmed milk powder by Berridge’s method. Cow’s milk used for coagulant strength determination and cheese-making. Proteolytic activity. The chemical determinations of raw milk were carried out according to AFNOR analysis methods. A descriptive sensory evaluation was performed to determine the organoleptic properties of the produced cheese. The proteolytic activity was determined by measuring the aspartyl-protease units. Results: The main results of the physico-chemical characterization show that its coagulant activity (R.U mL-1) was 97.19 ± 4.67, coagulant strength (SU) was 230.05 ± 0.37, proteolytic activity (μg·mL-1) was 0.33 ± 0.04 and coagulant activity/proteolytic activity ratio was 294.51. For the cheese made, it has presented the following results as % (g/100g): titrable acidity 0.80 ± 0.005, total dry extract 30.48 ± 1.490, fat 2.32 ± 0.02, fresh yield 11.5 ± 0.09, dry yield 30.06 ± 0.05. Moreover, sensory analysis results showed that fresh cheese prepared from Pergularia tomentosa dried leaves diluted enzymatic extract filtrate was characterized by whitish color, smooth texture, with acceptable and satisfying lactic taste. Conclusion: The plant enzymatic system studied could be added to the list of plant rennet substitutes and, thus, contributes to the manufacture of enzymatic coagulation cheese.