Effect of Hot Water Treatments on Quality of Highbush Blueberries

• Published in: Journal of food science 2008-08, Vol.73 (6), p.M292-M297
• Main Authors: Fan, L, Forney, C.F, Song, J, Doucette, C, Jordan, M.A, McRae, K.B, Walker, B.A
• Format: Article
• Language: English
• Subjects: aerobes; appearance (quality); Bacteria - growth & development; Berries; Biological and medical sciences; blueberries; blueberry; Blueberry Plants - microbiology; blueberry storage; Botrytis cinerea; Colletotrichum; Comparative analysis; Consumer Behavior; Consumer Product Safety; decay; Effects; firmness; flavor; food contamination; Food industries; food microbiology; Food Preservation - methods; Food science; food spoilage; food storage; Fruit - microbiology; Fruit - standards; Fruit and vegetable industries; fruit composition; fruit quality; Fundamental and applied biological sciences. Psychology; Fungi; Fungi - growth & development; Hot Temperature; hot water treatment; hot water treatments; Hydrogen-Ion Concentration; microbial contamination; molds (fungi); quality; soluble solids; storage temperature; storage time; Temperature; Time Factors; titratable acidity; Vaccinium; Water; weight; yeasts
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2008.00838.x

Highbush blueberries, cv 'Burlington', were treated with 22, 45, 50, or 60 °C water for 15 or 30 s along with an untreated control. Fruit were then stored for 0, 1, 2, or 4 wk at 0 °C and 2 or 9 d at 20 °C prior to evaluation of microbial population and fruit quality. After 4 wk of storage, the hot water treatment at 60 °C resulted in 92% marketable berries, followed by 90% at 50 °C, 88% at 45 °C, and 83% at 22 °C compared with 76% in untreated controls. Decay incidence was reduced to 0.6%, 1.2%, 1.4%, or 2.8% with 60, 50, 45, or 22 °C water treatments, respectively, compared with 5.1% in controls following 4 wk at 0 °C and 2 d at 20 °C. After an additional 7 d at 20 °C, decay in fruit treated at 60 °C for 15 or 30 s remained at 1.8% and 0.4%, respectively, compared to 37.4% in controls. Weight loss of berries treated with hot water was 0.4% against 3.8% in controls, and shriveled and split berries were also reduced compared to controls (P < 0.001). Aerobic plate count and yeast and mold count were reduced by 0.45 to 0.7 log at 60 °C for 30 s. Botrytis cinerea and Colletotrichum sp. were the dominant fungal pathogens causing decay of Burlington blueberries during storage. Hot water treatments also immediately induced an increase in ethanol and reduced fruit titratable acidity and soluble solids content, but had no significant effect on fruit firmness, pH, or most flavor volatile concentrations.