PSV-B-27 - The effects of carbohydrate hydrocolloids on firmness, toughness, and expressible moisture of wet pet food

In a previous experiment, inclusion of guar gum, kappa carrageenan, locust bean gum, and xanthan gum were observed to influence the texture of wet pet food. However, limited published research has addressed their texture and water holding. Therefore, the objective was to quantify the differences in texture and expressible moisture (EM) due to common hydrocolloids in wet pet foods. Treatments included 1% dextrose (D) and 0.5% guar gum with either 0.5% dextrose (DG), 0.5% kappa carrageenan (KCG), 0.5% locust bean gum (LBG), or 0.5% xanthan gum (XGG) in a chicken-based product processed in three replicate batches. Processing occurred in a still retort at 121 ℃ and 144.79 kPa for an average 81.25 minute cook cycle and 79.58 minute cooling cycle. Texture analysis was conducted with a modified back extrusion while products remained in the can (n = 5) and firmness (peak force measurement) and toughness (positive area under the curve) were recorded during a 2 cm penetration. Expressible moisture was analyzed by centrifugal methods. Data were analyzed as a 1-way ANOVA with the fixed effect of treatment and the random effect of batch. Fisher’s LSD post hoc test was used to separate means. The KCG treatment exhibited the highest (P < 0.05) firmness (27.00 N) and D and DG the lowest (average 8.75 N) with LBG and XGG intermediate (average 15.59 N). More differentiation was noted in toughness, with D (67 N x mm) less tough (P < 0.05) than DG (117 N x mm). The D treatment had the highest (P < 0.05) EM (49.91%) and was the only treatment to separate into 2 phases. The LBG and XGG treatments had the lowest (P < 0.05) EM (average 16.54%) with DG and KCG intermediate (average 25.26%). Carbohydrate hydrocolloids utilize different mechanisms to provide structure, which likely caused the differences in texture and EM observed.