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1.
Food Chem ; 289: 453-460, 2019 Aug 15.
Article in English | MEDLINE | ID: mdl-30955636

ABSTRACT

Carrot residues were upgraded as pectin-enriched fractions (PEFs) useful for functional food formulation due to co-extracted antioxidants (α- and ß-carotenes, lutein, α-tocopherol), and gelling effect. High power ultrasound (US)-enzyme assisted extraction was applied for efficiency and sustainability. Carrot powder (CP) in citrate-buffer (pH 5.20) was submitted to US-pretreatment (12.27 W/cm2: 20 kHz, 80% amplitude, 20 min) and a subsequent digestion (5 h-40 °C) without or with hemicellulase or cellulase. US-hemicellulase led to the highest PEF yield (27.1%), and extracted almost the whole pectin content of CP. US-pretreatment increased the extraction yield of all PEFs, but the existence of an additional positive effect of the following step depended on the enzyme used. PEFs contained 40-47% of UA with low DM (24-49.9%), and co-extracted antioxidants. US decreased the antioxidant contents, DM, and molecular weight, but allowed obtaining calcium crosslinked true gels, also with higher elastic modulus than non-US-extracted PEFs, being promising as food additives.


Subject(s)
Antioxidants/isolation & purification , Daucus carota/chemistry , Pectins/isolation & purification , Carotenoids/isolation & purification , Cellulase/metabolism , Food Handling/methods , Lutein/isolation & purification , Plant Roots/chemistry , Ultrasonics , alpha-Tocopherol/isolation & purification
2.
Mater Sci Eng C Mater Biol Appl ; 36: 108-17, 2014 Mar 01.
Article in English | MEDLINE | ID: mdl-24433893

ABSTRACT

Mixture design methodology was applied to study the effect of different levels of tapioca starch (TS), hydroxypropyl methylcelullose (HPMC), and glycerol (Gly) on the physical properties of biopolymeric films supporting potassium sorbate (KS; 0.3% w/w) with the goal of contributing to the development of materials for preventing food surface contamination. Mechanical properties, water vapour permeability (WVP), solubility in water (S) and colour attributes were evaluated on the films. HPMC addition produced an increase of elastic modulus (Ec), stress at break (σb) and S. It also decreased the yellow index (YI) values and the strain at break (εb). The study was deepened using the formulation containing 2.67 g/100g of TS, 0.67 g/100g of HPMC, 1.67 g/100g Gly and 0.3g/100g KS, observing that it behaved as an effective antimicrobial barrier against Zygosaccharomyces bailii external contamination. Microstructural analysis allowed us to conclude that HPMC incorporation to a TS network decreased roughness of the films and it also increased permeability to oxygen (PO2).


Subject(s)
Anti-Infective Agents/pharmacology , Biofilms/drug effects , Biopolymers/chemistry , Glycerol/pharmacology , Methylcellulose/analogs & derivatives , Physical Phenomena , Starch/pharmacology , Hypromellose Derivatives , Manihot/chemistry , Methylcellulose/pharmacology , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Permeability , Solubility , Spectroscopy, Fourier Transform Infrared , Steam , Water
3.
J Agric Food Chem ; 57(15): 6844-55, 2009 Aug 12.
Article in English | MEDLINE | ID: mdl-19610645

ABSTRACT

An edible film to carry l-(+)-ascorbic acid (AA) was formulated for natural antioxidant food protection. Considering previous works where films based on the "rigid" structure of gellan (deacylated) or on a mixture of acylated-deacylated (more "disordered") gellan were used for network development, pectin was herein chosen by considering that the alternating presence of "disordered" (hairy) regions together with ordered (homogalacturonan) ones could sufficiently immobilize water for better AA retention and lower browning. High methoxyl pectin (HMP) was first investigated. AA stability and browning were studied during film storage at 33.3, 57.7, or 75.2% relative humidity (RH) and 25 degrees C; their dependence on water mobility determined through (1)H NMR analysis as well as the correlation between browning and AA degradation were again found. Network characteristics and glycerol (plasticizer) interactions were analyzed through X-ray diffraction and Fourier transform infrared spectroscopy as well as through uniaxial tensile assay. From all results obtained, it was hypothesized that browning development in solidlike systems may be directly related to the water molecules more closely adsorbed on the hydroxyl-polymeric (active) surfaces. The HMP film microstructure produced the best immobilization of water molecules except at 75.2% RH, where it showed lower AA stability than acylated-deacylated gellan film. It is suggested that disordered regions of this pectin network may not be adequately counterbalanced by more transient junction zones of alternating hydrophilic (water) and hydrophobic (methyl ester) interactions, also disturbed by glycerol molecules, for accomplishing enough water immobilization in the whole network at 75.2% RH.


Subject(s)
Ascorbic Acid/chemistry , Food Packaging/instrumentation , Pectins/chemistry , Polymers/chemistry , Molecular Weight , Permeability , Tensile Strength , X-Ray Diffraction
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