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Physical, structural and antioxidant properties of brewer's spent grain protein films
Author(s) -
Proaño Janina L,
Salgado Pablo R,
Cian Raúl E,
Mauri Adria,
Drago Silvina R
Publication year - 2020
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.10597
Subject(s) - peg ratio , ultimate tensile strength , polyethylene glycol , solubility , plasticizer , chemical engineering , peg 400 , abts , chemistry , materials science , nuclear chemistry , active packaging , elastic modulus , antioxidant , organic chemistry , composite material , food packaging , food science , finance , dpph , engineering , economics
BACKGROUND The development of brewer's spent grain protein (BSG‐PC) films with potential active packaging properties was investigated. Films were prepared by casting protein dispersions at different pH values (2, 8, 11), plasticizers [polyethylene glycol (PEG) or glycerol] and levels (0–0.25 g g −1 ) of PEG. Mechanical, water‐barrier and solubility, optical, antioxidant (reducing power, ABTS •+ and lipidic radical scavenging), and antimicrobial properties of films were determined. Also, the structural characteristics of films were evaluated by attenuated total reflectance‐Fourier transform infrared spectroscopy. RESULTS Only films prepared at pH 2 and plasticized by PEG were homogeneous in appearance and could be manipulated; thus, different levels of PEG were studied at this pH. Higher PEG concentrations increased water solubility, water vapor permeability and elongation at break, and decreased tensile strength and elastic modulus. PEG increased α‐helix structure only when 0.10 g PEG g‐1 BSG‐PC was used. This could be related to the better mechanical properties of F 0.10 films (higher tensile strength, and elastic modulus) with respect to the other films. Antioxidant activity depended on PEG concentration, whereas no antimicrobial properties against Bacillus cereus , Salmonella newport and Penicillium corylophylum were detected. CONCLUSION The formulations with 0.10 and 0.15 g PEG g −1 BSG‐PC appear to be the most promising, balancing mechanical, water‐barrier properties and the antioxidant capacity of these films. Moreover, BSG proteins could be a cheap alternative for the preparation of biodegradable films, which are capable of being used as active food packaging. © 2020 Society of Chemical Industry