115 - Stability of Thiamine Supplied by Vitamin Premix and Yeast Ingredients in Canned Cat Food

Despite numerous process modifications, thiamine retention of canned cat food has not improved. Yeasts possess a binding protein which may provide a thiamine form able to withstand retort processing. Therefore, the objective was to evaluate dried yeasts as thiamine sources in canned cat food. Treatments were arranged as a 2ｘ4 factorial with 2 levels of vitamin premix (with or without) and 4 sources of yeast (none (NY), LBV, BY, or EA). Inclusion of LBV matched the thiamine contribution from the vitamin premix and BY and EA were capped at 5%. Three replicates were processed in a horizontal still retort to an average total F₀ of 79.23 minutes. Thiamine degradation was calculated as the difference between pre- and post-retort thiamine contents. Data were analyzed as a randomized complete block design with pre-retort thiamine content as a covariate and production day as a random effect. The Fisher’s LSD post hoc comparison test was performed with ⍺ = 0.05. On average, experimental formulas retained 33.75% thiamine. Thiamine degradation was not affected by the inclusion of vitamin premix (P = 0.0670), but was affected by the inclusion of yeast (P = 0.0232) and the interaction between vitamin premix and yeast (P = 0.0002). Thiamine loss between NY (-31.3 mg/kg DM) and BY (-33.8 mg/kg DM) were similar (P > 0.05) whereas EA (-40.5 mg/kg DM) and LBV (-55.6 mg/kg DM) lost more (P < 0.05) thiamine than NY. The treatment of EA with vitamin premix (-70.3 mg/kg DM) lost more (P < 0.05) thiamine than no yeast, BY, or EA without vitamin premix (average -17.4 mg/kg DM) and all others (average -57.3 mg/kg DM) were intermediate (P > 0.05). Inclusion of vitamin premix with yeast did not minimize thiamine loss and BY exhibited similar thiamine degradation as intrinsic thiamine in standard ingredients.