The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependant on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation.
Al-Ruqaie I., Kasapis S. and Abeysekera R. ( 1997). Structural properties of pectin-gelatin gels. Part II: Effect of sucrose/glucose syrup. Carbohydrate Polymers34: 309-321.
2.
Attia H., Bennasar M., Lagaude A., Hugodo B., Rouviere J. and Tarodo De La Fuente B. ( 1993). Ultrafiltration with microfiltration membrane of acid skimmed and fat-enriched milk coagula: hydrodynamic, microscope and rheological approaches. Journal of Dairy Research60: 161-174.
3.
Barfod N.M. and Pederson K.S. ( 1990). Determining setting temperature of high-methoxy pectin gels. Food Technology44: 139-148.
4.
BeMiller J.N. ( 1986). An introduction to pectins: Structure and properties . In: Fishman M.L. and Jen J.J. (eds), Chemistry and Function of Pectins. Washington: American Chemical Society, pp. 2-12.
5.
Blakney A.B., Harris P.J., Henry R.J. and Stone B.A. ( 1983). A simple and rapid preparation of aldithol acetates for monosaccharide analysis. Carbohydrate Research113: 291-299.
6.
De Vries J.A., Voragen A.G.J., Rombouts F.M. and Pilnik W. ( 1986). Structural studies of apple pectins with pectolytic enzymes . In: Fishman M.L. and Jen J.J. (eds), Chemistry and Function of Pectins. Washington: American Chemical Society, pp. 38-48.
7.
Diaz-Rojas E.I., Pacheco-Aguilar R., Lizardi J., Argüelles-Monal W., Valdez M.A., Rinaudo M. and Goycoolea F.M. ( 2004). Linseed pectin: Gelling properties and performance as an encapsulation matrix for shark liver oil. Food Hydrocolloids18: 293-304.
8.
Evageliou V., Richardson R.K. and Morris E.R. ( 2000). Co-gelation of high methoxy pectin with oxidized starch for potato maltodextrin. Carbohydrate Polymers42: 233-243.
9.
Fishman M.L., Pfeffer P.E., Baford R.A. and Doner L.W. ( 1984). Studies of pectin solution properties by high performance size exclusion chromatography. Journal of Agricultural Food Chemistry32: 372-378.
10.
Grant G.T., Morris E.R., Rees D.A., Smith P.J.C. and Thom D. ( 1973). Biological interactions between polysaccharides and divalent cations: The egg-box model. FEBS Letters32: 195-198.
11.
Grosso C.R.F. and Rao M.A. ( 1998). Dynamic rheology of structure development in low-methoxyl pectin + Ca2+ + sugar gels. Food Hydrocolloids12: 357-363.
12.
Guillotin S.E. ( 2005). Studies on the intra- and intermolecular distributions of substituents in commercial pectins. PhD Thesis, Wageningen University,The Netherlands.
13.
Iglesias M.T. and Lozano J.E. ( 2004). Extraction and characterisation of sunflower pectin. Journal of Food Engineering62: 215-223.
14.
Löfgren C., Guillotin S., Evenbratt H., Schols H. and Hermansson A.M. ( 2005). Effects of calcium, pH, and blockiness on kinetic rheological behavior and microstructure of HM pectin gels. Biomacromolecules6: 646-652.
15.
Löfgren C., Guillotin S. and Hermansson A.M. ( 2006). Microstructure and kinetic rheological behaviour of amidated and nonamidated LM pectin gels. Biomacromolecules7: 114-121.
16.
Löfgren C. and Hermansson A.M. ( 2007). Synergistic rheological behaviour of mixed HM/LM pectin gels. Food hydrocolloids21: 480-486.
17.
Löfgren C., Walkenstrom P. and Hermansson A.M. ( 2002). Microstructure and rheological behavior of pure and mixed pectin gels. Biomacromolecules3: 1144-1153.
18.
Lootens D., Capel F., Durand D., Nicolai T., Boulenguer P. and Langendorff V. ( 2003). Influence of pH, Ca concentration, temperature and amidation on the gelation of low methoxyl pectin. Food hydrocolloids17: 237-244.
19.
Lopes da Silva J.A. and Rao M.A. ( 1999). Reological Behaviour of Food Gel Systems. Rheology of Fluid and Semi-solid Foods. Maryland: Aspen Publishers Inc., pp. 319-368.
20.
Masmoudi M. ( 2009). Contribution à la valorisation des fractions glucidiques et pectiques de co-produits de dattes (Phoenix dactylifera L.) et de citron (Citrus limon L.). PhD Thesis, Ecole Nationale D’ingénieurs De Sfax, Tunisie.
21.
Masmoudi M., Besbes S., Blecker C. and Attia H. ( 2007). Preparation and characterization of osmodehydrated fruits from lemon and date by-products. Food Science Technology International13: 405-412.
22.
Masmoudi M., Besbes S., Chaabouni M., Robert C., Paquot M., Blecker C. and Attia H. ( 2008). Optimization of pectin extraction from lemon by-product with acidified date juice using response surface methodology. Carbohydrate Polymers74: 185-192.
23.
Matia-Merino L., Lau K. and Dickinson E. ( 2004). Effect of low-methoxyl, amidated pectin and ionic calcium on rheology and microstructure of acid-induced sodium caseinate gels. Food Hydrocolloids18: 271-281.
24.
May C. ( 1990). Industrial pectins: sources, production and applications . Carbohydrate Polymers12: 79-99.
25.
Oakenfull D.G. and Scott A. ( 1984). Hydrophobic interaction in the gelation of high methoxyl pectins. Journal of Food Science49: 1093-1098.
26.
Pilnik W. and Voragen A.G.J. ( 1970). Pectin substances and other uronides. In: Hulme A.C. (ed.), The Biochemistry of Fruits and their Products. New York: Academic Press, pp. 53-87.
27.
Rolin C. and Devries J. ( 1990). Pectin. In: Harris P. (ed.), Food Gels. New York: Elsevier, pp. 401-434.
28.
Rombouts F.M. and Thibault J.-F. ( 1986). Sugar beet pectins: chemical structure and gelation through oxidative coupling. In: Fishman M.L. and Jen J.J. (eds), Chemistry and Function of Pectins. Washington: American Chemical Society, pp. 49-60.
29.
Stading M., Langton M. and Hermansson A.M. ( 1993). Microstructure and rheological behaviour of particulate β-lactoglobulin gels. Food Hydrocolloids7: 195-212.
30.
Thakur B.R., Singh R.K. and Handa A.K. ( 1997). Chemistry and uses of pectin - a review. Critical Reviews in Food Science and Nutrition37: 47-73.
31.
Thibault J.F. and Ralet M.C. ( 2003). Physico-chemical properties of pectins in the cell walls and after extraction. In: Voragen F., Schols H. and Visser R. (eds), Advances in Pectin and Pectinase Research. Heidelberg: Springer, pp. 91-105.
32.
Voragen A.G.J., Schols H.A. and Pilnik W. ( 1986). Determination of the degree of methylation and acethylation of pectins by HPLC. Food Hydrocolloids1: 65-70.
33.
Walkenström P., Kidman S., Hermansson A.M., Rasmussen P.B. and Hoegh L. ( 2003). Microstructure and rheological behaviour of alginate/pectin mixed gels. Food hydrocolloids17: 593-603.
34.
Whistler R.L. and BeMiller J.N. ( 1997). Pectins. In: St. Paul M.N. (ed.), Carbohydrate Chemistry for Food Scientists,American Association of Cereal Chemists, St. Paul, MN: Eagan Press, pp. 203-210.
