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Preparation of citrus pectin gels by power ultrasound and its application as an edible coating in strawberries
Author(s) -
MuñozLabrador Ana,
Moreno Rodrigo,
Villamiel Mar,
Montilla Antonia
Publication year - 2018
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.9018
Subject(s) - pectin , rheology , food science , sugar , pulp (tooth) , chemistry , shear thinning , coating , apparent viscosity , pulp and paper industry , materials science , composite material , organic chemistry , medicine , pathology , engineering
BACKGROUND Pectin is heteropolysaccharide found in cell walls originating mainly from by‐products, as well as citrus peels, apple and sugar beet pulp, and presenting biological and techno‐functional properties. In the present study, a general and structural characterisation of industrial citrus pectins was performed together with a study of impact of power ultrasound (US) on their rheological properties, with the aim of using them as edible coatings for fresh strawberries. RESULTS The results obtained indicated that pure pectin showed a methylesterification degree greater than 50% and galacturonic acid content > 65%, supporting its consideration as additive E‐440; such conditions were not achieved in pectin with sugar addition. Furthermore, in the rheological study, pectin gels showed a non‐Newtonian flow and pseudoplastic behaviour and presented different viscosity ranges depending on the preparation methods, including power US. Gels were used as edible coatings for fresh strawberries aiming to improve their quality during storage over a period of 5 days, controlling quality characteristics such as humidity loss, acidity and colour parameters ( L * , a * , b * , C, h °, Δ E ). CONCLUSION The results obtained demonstrate that US treatments give rise to pectin gels that can improve the quality of strawberries over their lifetime. © 2018 Society of Chemical Industry