Ice cream waste is the yeast of our problems: The valorization of waste ice cream into alcohol

Authors: Miller, Amanda; Renye Jr, John; Johnston, David; Thomas, Jennifer; Oest, Adam; Garcia, Rafael; Tomasula, Margaret

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Wasted food that is discarded during manufacture is a concern to the food industry as many people don’t have access to food. In an attempt to reduce the amount of food waste, alternative methods are being investigated to convert food byproducts into higher value products that contribute back to the food supply chain. Many of these foods, especially dairy products, contain valuable food-grade components including fat, carbohydrates, and proteins. Ice cream manufacturing commonly results in the accumulation of wasted product that is difficult to be disposed of due to environmental concerns and the cost. This study showed that carbohydrates from wasted ice cream could be used as a fermentation substrate for the production of alcoholic beverages. This would be an example of a consumable product capable of being produced from waste ice cream since the distillation process is expected to remove allergenic proteins from the final product.

Technical Abstract: Food waste is a major problem when many people don’t have access to food. Valorization of food waste or food byproducts into higher value products can benefit the food industry by contributing to the food supply chain. This study aimed to investigate the potential for using ice cream waste as a fermentation substrate for production of ethanol by yeast. Results showed that two Saccharomyces cerevisiae strains, Lalvin EC-1118 and Ethanol Red, were able to ferment an aqueous co-product of waste ice cream resulting in the production of ethanol, ~7% (w/v). This most likely occurred due to the utilization of free monosaccharides or sucrose, because they were unable to ferment lactose. Lactase and glucoamylase were added to increase the availability of fermentable carbohydrates, resulting in 9.77% and 9.30% (w/v) ethanol produced by Lalvin EC-118 and Ethanol Red strains, respectively. Both strains were also shown to not utilize the galactose released following the hydrolysis of lactose. Maximum ethanol production, above 13% (w/v), was seen in samples treated with a combination of lactase and a protease, suggesting that a lack of nitrogen was stalling the fermentation. An analytical-scale distillation was performed using a fermented vanilla ice cream treated with protease, lactase, and diammonium phosphate. The distillation was successful and several fractions with various aromas and odors were collected. Results from this study suggest that that ethanol production is a viable valorization strategy to produce distilled beverage alcohol from waste ice cream, which is expected to be free of protein allergens.