Date of Award

2020

Document Type

Master Thesis

Degree Name

Masters of Science (Research)

Department

Biological Sciences

First Advisor

Dr Aoife McCarthy

Second Advisor

Dr Fiona O'Halloran

Abstract

Diets high in fruits and vegetables (FV), are widely recommended for their health-promoting properties. A low intake of FV among young adults, is associated with the risk of developing chronic diseases such as cardiovascular disease (CVD), hypertension, osteoporosis, obesity, type 2 diabetes, dental caries, hypercholesterolemia and certain cancers in later life. According to the World Health Organisation (WHO), despite an increasing awareness of the health benefits of FV, consumption by young adult’s remains below the recommended intake of 400g per day. This project aims to develop innovative, FV products for young adults with demonstrated bioactivity and high nutrient density. Initially, individual FV were screened for their potential antioxidant, antidiabetic and anticariogenic activity in vitro. As limited evidence exists on the interactions occurring between FV when combined, FV combinations were also assayed to identify synergistic or antagonistic effects. A range of antioxidant assays were carried out; DPPH radical scavenging activity, total phenolic content (TPC) and ferric reducing antioxidant power (FRAP). Antidiabetic potential was determined using α-amylase inhibition assay and antimicrobial activity against Streptococcus mutans was used to screen for anticariogenic activity. Blueberry, red pepper and sweet potato exhibited greatest TPC of all FV, and 75% of FV had a radical scavenging activity of > 90%. Red pepper and sweet potato displayed the greatest FRAP. Red grape possessed low bioactivity, while sweet potato was the FV with consistently high bioactivity across antioxidant and antidiabetic assays. Combining FV with low bioactivity resulted in synergistic interactions in DPPH radical scavenging and α-amylase inhibition. An antimicrobial effect was not observed in either individual or combined FV. Following screening of FV and combinations thereof, blueberry, strawberry and red pepper purees, were selected as a base for FV formulations. Additional ingredients including apple juice concentrate, protein hydrolysates, oats and fibre were added to further improve bioactivity and/or permit nutrition claims. Initially, 9 recipes were produced and analysed, which were then re-formulated to optimise bioactivity, sensory and nutritional attributes. In a total of 5 formulation trials (generating 33 beverages) were conducted, with the final trial being produced at pilot scale (5 beverages). Pilot-scale beverages were examined post-processing for their bioactivity, vitamin C content and techno-functional properties (colour, viscosity, sedimentation, volatile analysis). Results allowed recommendation of an optimum beverage recipe with market potential. This recipe contained blueberry, strawberry, red pepper and carrot puree, and was selected as it had highest vitamin C content, displayed high antioxidant and antidiabetic potential and retained favourable techno-functional properties following processing and storage. In conclusion, a range of beverages containing FV purees and beneficial ingredients were optimised and analysed for their bioactivity, nutritional profile and techno-functional properties. An optimum beverage recipe was selected as a potential FV product for market, which could contribute to increasing FV consumption among young adults.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Access Level

info:eu-repo/semantics/openAccess

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