Introduction. Ultrafiltration (UF) is a single-unit operation for the clarification and fining of fruit juices. The purpose of the UF is to remove suspended solids as well as haze-inducing and turbidity-causing substances to obtain a clear juice during storage. Specifically, the polymerization of phenolic compounds and their interaction with other components (e.g., proteins) could cause a haze complex and turbidity in fruit juices, which can foul the ultrafiltration membrane. Materials and methods. Fresh pomegranate juice was clarified by the ultrafiltration process on a laboratory scale. In experimental tests performed according to the total recycle and the batch concentration mode, the effects of transmembrane pressure (TMP) and enzyme pre-treatment on permeation flux and quality of juice were studied. Results. With the total recycle mode, the effect of TMP on the color and clarity of clarified pomegranate juice was significant. The initial color of the raw pomegranate juice was reduced from 74% to 33% and the clarity decreased from 77% to 42% by UF when the TMP increased from (1 to 3.6) bar. Total phenolic rejection decreased from 45% to 21% when the TMP rose from (1 to 2) bar and remained constant above this value. With the batch concentration mode at TMP = 2 bar and velocity 1 m·s–1, the enzymatic treatment (5 U·mL–1, 300 min, T = 20 °C) of pomegranate juice provided the highest permeate flux, a decrease in total phenolics of 50% and an increased clarity of 30%. Fouling of the UF membrane during pomegranate juice processing is mainly due to the retention of polyphenols and/or proteins; thus, several blocking mechanisms were studied, using a recently developed membrane-fouling model. Analysis revealed that the membrane separation process was controlled by the gel layer mechanism of raw pomegranate juice and complete pore blocking mechanism with enzymatic pre-treatment.

The objective of this study was the morphological characterization of the sheep population in the southwest of Tunisia. A joint analysis of quantitative and qualitative characters was carried out on 987 animals of three breeds: two local breeds (Barbarine (BAR) and Queue Fine de l'Ouest (QFG and QFT)) and an exotic breed introduced from Morocco, the D'man (DMN) breed.

Results on quantitative characters (height at withers (HG), body length (LC), thorax perimeter (PT), body weight of males (P♂) and body weight of females (P♀)) showed a significant superiority of the Queue Fine de l'Ouest breed compared to the other two breeds. On the other hand, results on qualitative characters (fleece color, horn and wattles) showed white to be the dominant color of the fleece in the Barbarine and Queue Fine breeds, while for the D'man breed there were various colors. Generally, females of the three breeds were polled while males were horned for the Queue Fine and polled for the Barbarine and D'man breeds. The Barbarine distinguishes itself from the other breeds by the total absence of wattles which are predominantly missing in the other two breeds.

Genetic distances estimated on the basis of quantitative characters showed that distances found between the Barbarine-D'man and Fine Tail of Ouest-D'man breeds were higher than those found between the Barbarine-Queue Fine breeds.

Introduction. Citrus aurantium L. sour oranges are poorly exploited in Tunisia, although the Tunisian Cap Bon is one of the major areas of production of sour orange trees. Our study aimed at determining the effect of the geographic origin of the raw material on quality of orange marmalades and consumer acceptance. Materials and methods. Fresh sour oranges were collected from five areas in the Cap Bon region in the North-East of Tunisia for producing marmalades. Physicochemical characterisation of marmalades from the five different origins included the determination of soluble solids, total and volatile acidity, the measurement of reducing sugars, and measurement of colour. Sensory panels from Tunisia, Algeria and Europe revealed the marmalades’ sensory profiles. The sensory panels then attributed preference and acceptance ranks for the five marmalades. Results and discussion. The analyses highlighted an effect of the geographic origin of the raw material on the physicochemical quality. The most suitable geographic conditions seem to be climatic and edaphic criteria. Assessors from various nationalities revealed different sensory profiles depending on the consumer’s nationality and fruit production region. In addition, Tunisian consumers are less likely to be marmalade buyers than European and Algerian consumers.

Introduction. The increase in diabetes and obesity has increased the demand for reduced sugar products such as jams and jellies. Four jelly formulations were prepared using date juice which was enriched with pectin and lemon flavors. Materials and methods. Reduced quantities of sugars (45% and 55%) were added to the juice at different pH (3 and 3.5). The prepared jellies were evaluated for physico-chemical and sensory properties. Results and discussion. The water activity values for jellies ranged between 0.767 and 0.804, making them safe from the development of the majority of bacteria. The addition of less quantity of sugar, as well as the decreased pH, resulted in significantly firmer jellies, with higher adhesiveness, chewiness and cohesiveness. Sensory evaluation showed that the prepared jellies averaged 4.17–5.47 and 4.59–5.67 for taste and firmness, respectively, in a 7-point hedonic scale consumer acceptance study. The most appreciated jellies were those prepared with the lowest sugar content, with a slight preference for that with a pH of 3.5. Significant differences were not found between scores for the other sensory attributes (color, transparency, brightness, odor and springiness).