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This study investigated the formation of oxo groups in pure solutions of barley mixed-linkage (1 → 3),(1 → 4)-β- d -glucans (MLGs) incubated in the presence of hydrogen peroxide or Fenton reaction-generated hydroxyl radicals ( OH), and it gives a fingerprint of products obtained after enzymic and acidic hydrolysis of OH-attacked MLG. Hydroxyl radical, but not hydrogen peroxide, introduced a range of NaB 3 H 4 -reducible functions into MLG chains. Driselase or lichenase digestion of NaB 3 H 4 -reduced MLGs released a complex mixture of 3 H-labelled products due to the presence of unusual and incompletely digestible residues in OH-attacked polysaccharide chains. Complete acid hydrolysis of OH-treated MLGs yielded a mixture of 3 H-aldoses (mainly glucose, mannose, galactose and allose) deriving from random OH attack at positions 2, 3 or 4 to form glycosulose residues which were NaB 3 H 4 -reducible to epimeric mixtures of 3 H-aldose residues. Furthermore, the production of [ 3 H]glucitol demonstrated the radical-mediated cleavage of mid-chain glucose residues to create new reducing termini. Oxidative scission of MLGs by hydroxyl radical caused a decrease in molecular weight of about 96%, which was partially inhibited by the addition of DMSO, an OH scavenger. The results can be a starting point for developing an assay to detect changes due to OH attack of MLGs in vivo , or during food processing and storage, based on the chemical or enzymic release of unusual sugar residues such as allose as diagnostic products after reduction/labelling treatment and partial purification (or selective digestion by lichenase) of polymeric material. [ABSTRACT FROM AUTHOR]

This work reports a novel enzyme-assisted process for lycopene concentration into a freeze-dried tomato matrix and describes the results of laboratory scale lycopene supercritical CO 2 (SC-CO 2 ) extractions carried out with untreated (control) and enzyme-digested matrices. The combined use of food-grade commercial plant cell-wall glycosidases (Celluclast/Novozyme plus Viscozyme) allows to increase lycopene (∼153%) and lipid (∼137%) concentration in the matrix and rises substrate load onto the extraction vessel (∼46%) compared to the control. The addition of an oleaginous co-matrix (hazelnut seeds) to the tomato matrix (1:1 by weight) increases CO 2 diffusion through the highly dense enzyme-treated matrix bed and provides lipids that are co-extracted increasing lycopene yield. Under the same operative conditions (50 MPa, 86 °C, 4 mL min − 1 SC-CO 2 flow) extraction yield from control and Celluclast/Novozyme + Viscozyme-treated tomato matrix/co-matrix mixtures was similar, exceeding 75% after 4.5 h of extraction. However, the total extracted lycopene was ∼3 times higher in enzyme-treated matrix than control. [ABSTRACT FROM AUTHOR]