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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Research Project #429418

Research Project: Enhancing Utilization of Citrus Processing Co-products

Location: Citrus and Other Subtropical Products Research

Project Number: 6034-41000-017-00-D
Project Type: In-House Appropriated

Start Date: Jul 28, 2015
End Date: Jul 27, 2020

Objective:
1. Enable, from a technological standpoint, new commercial products from pectic hydrocolloids derived from citrus processing. 2. Characterize and quantify bioactive flavonoid compounds from byproducts of citrus processing, determine their in vivo pharmacokinetics and bioavailability; and enable a new commercial delivery of bioactive flavonoids in food and feed by encapsulation with pectic hydrocolloids. 2A. Characterize and quantify bioactive flavonoid compounds from byproducts of citrus processing, determine their in vivo pharmacokinetics and bioavailability. 2B. Enable a new commercial delivery of bioactive flavonoids in food and feed by encapsulation with pectic hydrocolloids. 3. Enable a novel immunologically-based assessment of structural quality and functional properties of citrus pectin in raw and processed foods and industrial products.

Approach:
Experimentation is required to determine the necessary time, temperature and concentration conditions to enable pilot-scale functionalization of the released pectic hydrocolloids from steam explosion of peel material. Response surface methodology will be used to determine these parameters using analytical methods. Consequently, the variables of temperature, time and concentration of steamed peel waste will be manipulated to determine optimal conditions for functionalizing the released pectic hydrocolloids. Functionality will be assessed by measuring resulting calcium induced viscosity using a concentric cylinder viscometer and/or oscillatory measurements using a stress controlled rheometer and related to final degree of methylation, charge distribution and molecular weight (MW) of the modified pectic hydrocolloids. Compositional analysis and structural properties will be characterized by Size Exclusion Chromatography (SEC) coupled to Multi Angle Laser Light Scattering (MALLS), Refractive Index (RI) or Conductivity Detectors; High Performance Anion Exchange Chromatography (HPAEC) coupled to an Evaporative Light Scattering Detector (ELSD) or Pulsed Amperometric Detector (PAD) and enzymatic/chemical methods. Composition of the polysaccharides present in peel wash after steam explosion will be determined by enzymatic hydrolysis and liquid chromatography with electrochemical detection. Use of polysaccharide specific enzymes (arabinase, arabinofuranosidase, etc.) will allow for determination of the contribution of individual polysaccharides. Pectin populations will be examined via interaction with antibodies that bind to specific structural epitopes on individual pectin molecules. Pectin populations will be produced by enzymatic and/or chemical methods that contain various sizes of ionically-charged or neutral, methyl-protected domains. Elucidation of the modes of anti-inflammatory actions of the health promoting compounds in citrus byproducts will be accomplished by characterizing their metabolites and pharmacokinetics, and elucidating their biochemical actions at the cellular level using in vitro assay microplate technologies. These biochemical actions subsequently will be investigated in animal trials conducted through collaborations with other research laboratories or through commercial contract research laboratories. The research will first require the isolation and chemical characterization of mammalian metabolites of the test citrus byproduct compounds, and these isolations will be achieved through established chromatographic and HPLC-MS techniques.