Composition and thermal processing evaluation of yeast ingredients as thiamin sources compared to a standard vitamin premix for canned cat food

Abstract

Significant improvement in thiamin retention of canned cat food has not been achieved by altering processing conditions. Some ingredients, such as yeasts, may supply thiamin able to withstand thermal processing. Therefore, the study objective was to evaluate yeast ingredients as thiamin sources for canned cat food. Six yeast ingredients were screened for thiamin content, and values ranged from 9.9–4,283.8 mg/kg dry matter basis (DMB). Treatments for thermal processing were arranged as a 2×4 factorial with 2 levels of vitamin premix (with or without) and 4 yeast ingredients (NY = none and LBV, BY, or EA from the ingredient screening). Replicates (n = 3) were processed in a horizontal still retort to an average lethality of 79.23 minutes. Thiamin degradation was analyzed as a mixed model with pre-retort thiamin content as a covariate and production day as a random effect. Main effects of vitamin premix and yeast and their interaction were significant at P-values less than 0.05. The Fisher’s LSD post hoc comparison test was used to separate means. On average, experimental formulas retained 33.75% thiamin. The main effect of vitamin premix (average -42.9 mg/kg DMB) was not significant (P > 0.05). Thiamin degradation between NY (-31.3 mg/kg DMB) and BY (-33.8 mg/kg DMB) was similar (P > 0.05) whereas EA (-40.5 mg/kg DMB) and LBV (-55.6 mg/kg DMB) lost more (P < 0.05) thiamin than NY. The experimental formula of EA with vitamin premix (-70.3 mg/kg DMB) lost more (P < 0.05) thiamin than no yeast, BY, or EA without vitamin premix (average -17.4 mg/kg DMB) and all others (average -57.3 mg/kg DMB) were intermediate (P > 0.05). In summary, thiamin from yeast ingredients didn’t exhibit better thermal stability than thiamin mononitrate. However, those ingredients with similar degradation levels or uniquely high thiamin levels may provide added value.

Impacts of vitamin premix and/or yeast ingredient inclusion in a canned cat food on thiamin retention during 6 months of storage

“…This is likely due to the nutritional composition of the yeast ingredients and the brewer's rice used as a space-holding ingredient. The brewer's rice contained 9.2% DMB crude protein whereas the three yeast ingredients contained an average of 53.5% DMB crude protein ( 12 ). Diets containing LBV were intermediate in terms of crude protein content; this is likely due to the ingredient's lower inclusion level compared to BY and EA.…”

“…The experimental treatments and their production have been described previously ( 12 ). Briefly, 8 experimental treatments were arranged as a factorial with 2 categorical levels of vitamin premix (no vitamin premix or 0.08% vitamin premix containing thiamin mononitrate) and 4 categorical levels of dried yeast [no yeast (NY), 0.65% LBV, 5.00% BY, or 5.00% EA; Table 1 ].…”

“…The level of LBV (Lallemand Bio-Ingredients, a division of Lallemand Inc., Montréal, QC, CA) was chosen to match the thiamin supplied by the vitamin premix. However, formulation levels were based on a yeast ingredient screening analysis and the LBV used in experimental treatment production contained less thiamin than expected ( 12 ). The levels for BY (The Peterson Company, Kalamazoo, MI) and EA (The F.L.…”

“…This process created 8 canned diets to serve as experimental treatments for the storage study with ranging thiamin contents. Ranking the experimental treatments by their average thiamin contents immediately after processing appears as follows: NY without the vitamin premix (0.7 mg/kg DMB), EA without the vitamin premix (2.2 mg/kg DMB), BY without the vitamin premix (5.8 mg/kg DMB), LBV without the vitamin premix (19.9 mg/kg DMB), EA with the vitamin premix (46.5 mg/kg DMB), NY with the vitamin premix (54.7 mg/kg DMB), LBV with the vitamin premix (59.6 mg/kg DMB), and BY with the vitamin premix [60.7 mg/kg DMB; ( 12 )].…”

“…LBV) for their thiamin stability in a canned cat food through thermal processing. This research identified a spray-dried brewer's yeast (BY) with similar thermal degradation levels compared to thiamin mononitrate, the standard thiamin source for canned cat foods, and a fortified inactive yeast ingredient (LBV) with high levels of thiamin ( 12 ). While these were meaningful findings, previous research in extruded pet foods found that thiamin levels decreased during storage of the diet ( 13 ).…”