Improvement of microbiological safety and shelf-life of pulse spreads through sous vide and high pressure processing

A. Kirse*, R. Galoburda, S. Muizniece-Brasava, D. Karklina and L. Skudra

Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, 22 Rigas Street, LV3004, Jelgava, Latvia
*Correspondence: asnate.kirse@llu.lv

Abstract:

Microbiological quality of sous vide treated (80 °C/15 min) and high pressure processed (700 MPa/10 min/20 C) cowpea (Vigna unguiculata (L.) Walp. cv. Fradel) and maple pea (Pisum sativum var. arvense L. cv. Bruno) spreads in flexible vacuum packaging during 62-day storage at 5 ± 1 °C were assessed. Pulse spreads, made from cooked pulses with salt, citric acid, oil, and seasoning, were filled in PA/PE or PET/ALU/PA/PP flexible film pouches, packaged in vacuum (20 mbar) and hermetically sealed. Microbiological testing was performed by determining total plate count, yeast and mould count on days 0, 15, 29, 42, 50, 57, and 62, and the presence of B. cereus, C. perfringens and E. coli before processing and after 62-day storage. The results showed that total plate count increased significantly after 62-day storage in both sous vide (P = 0.011) and high pressure processed (P = 0.017) spreads; the observed over one-log increase was without significant differences between pulse spreads and packaging materials (P < 0.05). The admissible level of total plate count (Nmax < 3.69 log CFU g-1) in pulse spreads was not exceeded. The presence of yeasts and moulds, C. perfringens and E. coli in pulse spreads was not confirmed, whereas B. cereus accounted to <102 CFU g-1 after 62-day storage. The suggested shelf-life of processed pulse spreads is 62 days; except for sous vide treated spreads with seasoning in both packaging materials- 57 days. Both processing methods are suitable to ensure the production of high quality pulse spreads with adequately long shelf-life.

Key words:

Integrated evaluation of cowpea (Vigna unguiculata (L.) Walp.) and maple pea (Pisum sativum var. arvense L.) spreads

A. Kirse* and D. Karklina

Department of Food Technology, Faculty of Food Technology, Latvia University of Agriculture, 2 Liela Street, LV3001, Jelgava, Latvia *Correspondence: asnate.kirse@gmail.com

Abstract:

The aim of this research was to develop pea spreads using local legumes and complete integrated evaluation of the spreads to find the most suitable pea spreads for shelf-life investigation. A total of twelve pea spreads were made of ground re-hydrated cooked seeds of cowpeas (Vigna unguiculata (L.) Walp.) or maple peas (Pisum sativum var. arvense L.), to which salt, citric acid, oil and different spices were added. Standard analytical methods were employed to determine overall preference and physicochemical composition (protein, fibre, ash, pH, etc.) of spread samples. Principles of integrated evaluation were used to select the most suitable spreads for pea spread shelf-life investigation. The overall preference of cowpea and maple pea spread samples ranged from 2.8 to 4.9 with significant differences among spreads (P < 0.05). Physicochemical evaluation was completed with only sensory satisfactory samples. There were no significant differences in protein, ash and dry matter content among pea spread samples (P > 0.05). Pea spreads were good sources of total dietary fibre (10.72 to 14.81 g 100 g-1). Addition of spices had a significant impact on the lightness (L*) and firmness of pea spreads (P < 0.05). Cowpea spread with bruschetta spice (15.43) and maple pea spread with bruschetta spice (22.09) had the lowest integrated evaluation values among spreads from the same legume. It was concluded that shelf-life investigation should be completed with the most suitable spread (the lowest integrated evaluation value) and control sample, i.e., cowpea spread and maple spread with bruschetta spice and without spices.

Key words:

cowpea, maple pea, physicochemical evaluation, sensory evaluation.