Laser-backscattering imaging for characterizing pork loin tenderness. Effect of pre-treatment with enzyme and cooking

Raúl Grau^a, Samuel Verdú^a, Alberto J.Pérez^b, José M.Barat^a, Pau Talens^a

Departamento de Tecnología de Alimentos, Universitat Politècnica de València, Spain.

Abstract

The aim of this work was to characterizes, by the non-destructive technique based on the laser-backscattering imaging analysis, the effect of pre-treatment with papain enzyme (1% w/w), the enzyme action time (0, 3, 6 and 24 h at 4°C) and cooking (80°C for 3 min) on pork loin tenderness. Texture and image analyses were run for the untreated and treated samples, and for the uncooked and cooked samples. Images of the laser pattern generated on the meat surface were decomposed into red, green and blue channels. Two descriptors types (direct and relative) were developed for each one by segmentation. The obtained results revealed the increased tenderness in the samples that underwent enzyme treatment with maximum values at 6 h (29.3 ± 3.2 N). Cooking increased enzyme action with much lower values (39.2 ± 3 N) than for the samples without treatment (75.6 ± 2.9 N). For uncooked meat, changes in texture were related mainly to the relative descriptor of the blue and green channels, and those from the red channel for cooked meat, which allowed prediction models to be obtained (R² CV = 0.9; RMSE CV = 1.9).

Keywords: Meat softness, Papain, Diffuse reflectance, Biospeckle, Non-destructive analysis