Christophe Blecker

Effect of Pear, Apple and Date Fibres from Cooked Fruit By-products on Dough Performance and Bread Quality

This study examined the effect of the incorporation of flesh fibre concentrate (FFC) from apple, pear, and date pomaces on wheat bread dough performance and bread quality. The nutritional composition and techno-functional properties (water-holding capacity, oil-holding capacity, swelling capacity) of FFC were determined beforehand. Dough performance was evaluated by farinograph, alveograph and visco-amylograph. Bread quality was assessed by physical (weight, specific volume, and color) and textural (hardness and elasticity) parameters. Digital imaging analysis was also performed in order to better understand the observed effects. Results showed that the addition of FFC in wheat flour significantly improved (Pu2009<u20090.05) dough properties inducing an increase of water absorption (from 55 to 60xa0%), of stability (from 4 to 31xa0min),of tenacity (from 83 to 116xa0mmH2O) , a reduction of extensibility (from 69 to 29xa0mm), of softening (from 60 to 20xa0BU), of breakdown (from 34 to 25xa0BU) and of setback (from 103 to 93xa0BU) in comparison to the control dough (without fibre). The formulation containing FFC produced loaves that had various colors (crust, 0u2009<u2009ΔE*u2009<u200910 and crumb, 0u2009<u2009ΔE*u2009<u200920; ΔE* corresponding to color variation), a comparable specific volume (2.7 vs 2.9xa0cm3/g for control) and a more aerated internal crumb structure compared to the control. During storage of breads at 20xa0°C, there was no significant difference (Pu2009<u20090.05) between enriched and control bread crumb and crust texture profiles.

Improving halva quality with dietary fibres of sesame seed coats and date pulp, enriched with emulsifier

Supplementation of halva with waste products of manufacturing, for example defatted sesame seed coats (testae) and date fibre concentrate, can improve its nutritional and organoleptic qualities. These constituents provide high fibre content and technological potential for retaining water and fat. Standard halva supplemented with date fibre concentrate, defatted sesame testae and emulsifier was evaluated for oil separation, texture and colour changes, sensory qualities and acceptability to a taste panel. Addition of both fibres with an emulsifier, improved emulsion stability and increased the hardness of halva significantly. The functional properties of sesame testae and date fibres promote nutrition and health, supplying polyphenol antioxidants and laxative benefits.

Enzymatic process for the fractionation of baker’s yeast cell wall (Saccharomyces cerevisiae)

β-Glucans, homopolymers of glucose, are widespread in many microorganisms, mushrooms and plants. They have attracted attention because of their bioactive and medicinal functions. One important source of β-glucans is the cell wall of yeasts, especially that of bakers yeast Saccharomyces cerevisiae. Several processes for the isolation of β-glucans, using alkali, acid or a combination of both, result in degradation of the polymeric chains. In this paper, we have an enzymatic process for the isolation of glucans from yeast cell walls. As a result, β-glucans were obtained in a yield of 18.0% of the original ratio in the yeast cell walls. Therefore, this isolation process gave a better yield and higher β-glucan content than did traditional isolation methods. Furthermore, results showed that each extraction step of β-glucan had a significant effects on its chemical properties.

Adding Value to Agricultural Products and Agrifood Byproducts by Highlighting Functional Ingredients

1 University of Sfax, National School of Engineer, Laboratory of Valorization, Analysis and Food Safety, Soukra Road km 4.5, 3038 Sfax, Tunisia 2 Department of Applied Biotechnology, University of Sfax, Higher Institute of Biotechnology, Soukra Road km 4.5, 3038 Sfax, Tunisia 3 University of Liege, Gembloux Agro-Bio Tech. Laboratory of Food Science and Formulation, 2 Passage des Deportes, 5030 Gembloux, Belgium