Title: Compositional and Structural Characterization of Pectin Material from Frozen Concentrated Orange Juice Authors
Submitted to: Food Hydrocolloids Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 14, 2013
Publication Date: N/A
Interpretive Summary: Food fortification has become a key driver in selling nutritionally dense foods in a media that is proven to provide bio availability as well as tasting and looking appealing such as citrus juices. With the increase in fortification, assessing changes in pectin "quality" due to processing conditions and enzyme activity is critical in identifying raw material concentrates that are correct for producing nutritionally enhanced beverages and juices. Addition of various mineral species into a citrus juice matrix can dramatically impact the organoleptic quality of the juice. This is even worse in foodservice applications using high brix concentrates. Impact to the quality of the juice, including viscosity, can affect not only its sensory characteristics but also its ability to dispense. Here we are characterizing the pectin component of a commercial frozen concentrated citrus juice as a baseline for identifying changes that could yield a highly efficient way to prescreen concentrates to identify those that should be reconsidered prior to using in the production of nutritionally enhanced formulae.
Technical Abstract: Pectin is a structurally diverse polysaccharide synthesized in plants. Its core element is a backbone of a-( 1,4)-galacturonic acid residues, which may be interspersed with rhamnose residues, esterified, and decorated with a variety of glycan chains. In citrus juice, pectin comprises the majority of the suspended cloud material that imparts desirable texture and flavor. We have extracted pectin from commercial Citrus sinensis juice concentrate and assessed its macromolecular properties, including soluble sugar composition by High Performance Anion Exchange Chromatography – Pulsed Amperometric Detection and molecular weight and degree of methyl-esterification (DM) by Multi-Angle Laser Light Scattering – Size Exclusion Chromatography – differential Refractive Index-Capacitively Coupled Contactless Conductivity. The molecular weight of the pectin varied according to the enzymatic digestion method employed –from 1.5 x 106 Daltons for the parent material, to 1.4 x 103 Daltons when treated with Rapidase Adex-P. With an intact molecular weight in the millions of Daltons and a DM of 83.7%, the extracted pectin is markedly different from pectins extracted from other citrus sources.