High pressure processing of hummus: Enhancing microbial safety and stability, and reducing lipid oxidation.

Abstract

Hummus provides an ideal environment for microbial growth. The objectives of this study were to evaluate the effect of high-pressure processing (HPP) on i) microbial safety/quality, ii) physical/chemical properties, and iii) sensory characteristics of hummus. Uninoculated and hummus inoculated with Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes were subjected to HPP at 350 MPa for 1-5 min. After treatment, the D-value of the pathogens was calculated and uninoculated samples were stored for up to 28 d at 4 and 10 °C and total microbial counts (TMC) were enumerated. Thiobarbituric acid reactive substances (TBARS), colour, textural and rheological properties and sensory characteristics of hummus were also analysed. The D₁₀-value for Salmonella spp., E. coli O157:H7 spp. and L. monocytogenes were 2.10 ± 0.13, 1.48 ± 0.08, and 3.77 ± 0.36 min, respectively. As compared to the control, HPP for 1, 2, 3, 4, and 5 min instantly decreased TMC on average by 0.7, 1.2, 1.6, 1.4 and 1.8 log cfu/g, respectively. The shelf life of hummus in this study after an HPP treatment of 350 MPa for 2-5 min was 28 d at 4^oC and one week at 10 °C, while it was 14 d and 7 d in the control samples, respectively. HPP decreased TBARS but did not significantly change hummus lightness, greenness, and yellowness. HPP enhanced the gel strength and viscoelastic properties of hummus without compromising its sensory qualities. Thereby, HPP at 350 MPa for 1-5 min can be effective and adopted by producers.