Diacetyl levels and volatile profiles of commercial starter distillates and selected dairy foods

Abstract

Starter distillates (SDL) are used as ingredients in the formulation of many food products such as cottage cheese, margarine, vegetable oil spreads, processed cheese, and sour cream to increase the levels of naturally occurring buttery aroma associated with fermentation. This buttery aroma results, in part, from the presence of the vicinal dicarbonyl, diacetyl, which imparts a high level of buttery flavor notes and is a key component of SDL. Diacetyl (2,3-butanedione) is a volatile product of citrate metabolism produced by certain bacteria, including Lactococcus lactis ssp. diacetylactis and Leuconostoc citrovorum. In the United States, SDL are regarded as generally recognized as safe ingredients, whereby usage in food products is limited by good manufacturing practices. Recently, diacetyl has been implicated as a causative agent in certain lung ailments in plant workers; however, little is published about the volatile composition of SDL and the levels of diacetyl or other flavoring components in finished dairy products. The objective of this work was to characterize the volatile compounds of commercial SDL and to quantitate levels of diacetyl and other Flavor and Extract Manufacturers Association-designated high-priority flavoring components found in 18 SDL samples and 24 selected dairy products. Headspace volatiles were assessed using a solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. In addition to diacetyl (ranging from 1.2 to 22,000 μg/g), 40 compounds including 8 organic acids, 4 alcohols, 3 aldehydes, 7 esters, 3 furans, 10 ketones, 2 lactones, 2 sulfur-containing compounds, and 1 terpene were detected in the SDL. A total of 22 food samples were found to contain diacetyl ranging from 4.5 to 2,700 μg/100g. Other volatile compounds, including acetaldehyde, acetic acid, acetoin, benzaldehyde, butyric acid, formic acid, furfural, 2,3-heptanedione, 2,3-pentanedione, and propanoic acid, were also identified and quantified in SDL or food samples, or both. The results obtained in this work summarize the volatile composition of commercial SDL and the approximate levels of diacetyl and other Flavor and Extract Manufacturers Association-designated high-priority flavoring components found in SDL and selected dairy foods.

Contribution of volatiles to the antifungal effect of Lactobacillus paracasei in defined medium and yogurt

“…The influence of added ALDC on inhibition of P. solitum DCS 302 was tested after fermentation at 37°C/24 h. Plates were incubated at 25°C until mold growth appeared. Diacetyl is a common volatile metabolite in fermented milk products (Ott et al, 2000) with reported concentrations between 0.045 and 27 μg/g depending on the product (Rincon-Delgadillo et al, 2012). The presence of diacetyl and acetoin contributes positively to the buttery or creamy flavor perception but the range of sensory acceptable levels varies between different dairy products.…”

Diacetyl in Foods: A Review of Safety and Sensory Characteristics

“…To increase the levels of the natural buttery aroma associated with fermentation, starter distillates (SDL) are commonly used as ingredients in the formulation of many food products, including cottage cheese, margarine, salad dressings, sauces and gravies, snacks, soups, frosting mixes, vegetable oil spread, process cheese, baked goods, beverages, and sour cream (Rincon‐Delgadillo and others ). The SDL are defined as steam distillates obtained by fermentation of a medium containing skim milk fortified with citric acid, which is fermented by specific lactic acid bacteria; SDL are GRAS (CFR ).…”

“…Diacetyl is the primary component of SDL, while 8 other compounds are also produced (CFR ). SDL are available as water‐ or oil‐based liquid or as encapsulated powder; usage in food products is limited by good manufacturing practices (Rincon‐Delgadillo and others ). Rincon‐Delgadillo and others () characterized the volatile compounds of commercial SDL and quantitated levels of diacetyl and other Flavor and Extract Manufacturers Association‐designated high‐priority flavoring components found in 18 SDL samples and 24 selected dairy products using SPME‐gas chromatography (GC)‐mass spectrometry (MS).…”

“…SDL are available as water‐ or oil‐based liquid or as encapsulated powder; usage in food products is limited by good manufacturing practices (Rincon‐Delgadillo and others ). Rincon‐Delgadillo and others () characterized the volatile compounds of commercial SDL and quantitated levels of diacetyl and other Flavor and Extract Manufacturers Association‐designated high‐priority flavoring components found in 18 SDL samples and 24 selected dairy products using SPME‐gas chromatography (GC)‐mass spectrometry (MS). The diacetyl content ranged from 1.2 to 22000 ppm in the SDL samples and from 0.05 to 27 ppm in 22 out of 24 of the dairy products tested that listed either “natural flavor” or “natural and artificial flavor” on the labels.…”

Preparation of optically active 4-substituted γ-lactones by lipase-catalyzed optical resolution

“…These lactones are present in a wide variety of natural products, such as mango [12,13] , peach [14,15] , strawberry [16,17] , Gouda cheese [18,19] , and other dairy products [20,21] .…”