Microwave-assisted extraction in goji berries: effect on composition and bioactivity, evaluated through conventional and nonconventional methodologies

• Published in: International journal of food science & technology Vol. 51; no. 6; pp. 1401 - 1408
• Main Authors: Carvalho, Ana P., Mendes, Marta, Moreira, Manuela M., Cruz, Diana, Magalhães, Júlia M. C. S., Barroso, M. Fátima, Ramalhosa, M. J., Duarte, Abel, Guido, Luís, Gomes, Ana M., Matos, Cristina Delerue
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.06.2016; Wiley Subscription Services, Inc
• Subjects: Antiinfectives and antibacterials; Antioxidants; Ascorbic acid; Berries; Bioactive compounds; Biochemistry; Biocompatibility; biosensor; electrochemical methods; Extraction; Food science; HPLC-DAD; Lycium barbarum; microwave-assisted extraction; Microwaves; Sensors; spectrophotometric methods; Spectrophotometry
• ISSN: 0950-5423; 1365-2621
• DOI: 10.1111/ijfs.13105

Summary This study aimed to evaluate the effect of microwave‐assisted extraction (MAE) parameters on the composition and bioactivity of goji (Lycium barbarum) extracts. Extracts were obtained under a central composite design combination of experimental conditions, and characterised through HPLC‐DAD; their bioactive capacity was ascertained for antimicrobial and antioxidant capacity, the later by spectrophotometric [2,2‐azinobis (3‐ ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt‐radical scavenging activity assay – 413–748 mg ascorbic acid equivalents/100 g DW and oxygen radical absorbance capacity – 1901–2292 mg trolox equivalents/100 g DW] and electrochemical (DNA‐based sensor – 3571–6602 mg ascorbic acid/100 g DW) methods. The quantitative profile of phenolic compounds was strongly dependent on MAE conditions. Significant correlations were found between the presence of several flavonoids and solvent composition, as well as between phenolic acids with methoxy group and the response to DNA‐based sensor. Results may improve targeted extractions for specific compounds, leading to the achievement of extracts richer in antioxidant capacity, as well as in the tailoring of the biosensor response sensitivity to the composition of the extracts under analysis. Goji extracts, obtained by MAE, were characterised through HPLC and their bioactive capacity was ascertained in terms of antimicrobial and antioxidant capacity, the later by spectrophotometric and electrochemical methods.