Effects of microbial lipases on hydrolyzed milk fat at different time intervals in flavour development and oxidative stability

Abstract

The interest in application of biocatalysis during natural milk fat flavours development has increased rapidly and lipases have become the most studied group in the development of bovine milk fat flavours. Lipozyme-435, Novozyme-435 and Thermomyces lanuginosus Immobilized (TL-IM) lipases were used to hydrolyze anhydrous milk fat (AMF) and anhydrous buffalo milk fat (ABF) and their volatile flavouring compounds were identified by solid-phase micro-extraction gas chromatography/mass spectrometry (SPME-GC/MS) and then compared at three hydrolysis intervals. Both AMF and ABF after lipolysis produced high amount of butanoic and hexanoic acids and other flavouring compounds; however, highest amount were produced by Lipozyme-435 and Novozyme-435 followed by TL-IM. The hydrolyzed products were assessed by Rancimat-743 for oxidative stability and found both that, for AMF and ABF treated butter oil, Lipozyme-435 and TL-IM were generally more stable compared to Novozyme-435. For both AMF and ABF treated butter oil, Lipozyme-435 was observed to cause no further oxidation consequences which indicates Lipozyme-435 was stable during hydrolysis at 55°C for 24 h.

Prospecting the Potential of Agroresidues as Substrate for Microbial Flavor Production

“…Lipases can be successfully utilized for modification of skim milk (0.5% fat) into full-fat milk flavor by producing volatile flavor components (Zhang et al, 2016). In a study by Omar et al (2016), lipases were used to hydrolyze anhydrous milk fat for the development of milk fat flavors due to the synthesis of volatile flavoring esters, acids, and ketones. Interestingly, lipases can also resolve D, L-methylmenthol esters into pure L-menthol (Schreier, 2006).…”

Triacylglycerol composition, melting and crystallization profiles of lipase catalysed anhydrous milk fats hydrolysed

“…Hydrolysis of AMF with Lipozyme-435 and Novozyme-435 was carried out at 55°C in a 125-mL Erlenmeyer flask as described in detail in our previous study. [20,22] Ultra pressure liquid chromatography analysis…”

“…[19,21] Coincidentally, the short-chain fatty acids that are targeted for the development of flavour such as butyric, caproic, and octanoic acids are also located at sn_1,3 positions of a TAG molecule. [18,20,22] For this reason, controlled hydrolysis of TAGs by careful selection of enzyme and timing enzyme reaction is essential in the development of desirable flavour. This implies that some of the TAGs will be partially hydrolysed while others will still remain intact.…”

“…However, from the available literature, very little has been reported about the properties of TAGs in milk fat after enzymatic hydrolysis. On the other hand, studies conducted by Neff and Byrdwell [22,23] revealed that the oxidative stability of soya bean oil was partly dependent on the TAGs composition and their structure.…”

Characterization of Microbial Community Composition in the Fermentation Starter (Daqu) Reveals a Distinct Dominant Species Combination Potentially Contributing to the Flavor of Chinese Gujingtribute Liquor

“…Aziz et al (2015) [15] investigated a lipase from Thermomyces lanuginosus in terms of their efficiency for the hydrolysis of safflower oil for the liberation of free linoleic acid used as a flavor precursor. Omar et al (2016) [16] employed immobilized lipase from Thermomyces lanuginosus to hydrolyze anhydrous milk fat and anhydrous buffalo milk fat, then used solid-phase micro-extraction gas chromatography/mass spectrometry to identify volatile flavouring compounds, and observed high amount of butanoic and hexanoic acids and other flavor compounds. Another report [17] suggested that Thermomyces lanuginosus lipase's one specific region can adopt a structural change at the water-lipid interface (which occurs during solid fermentation process of GujingTribute liquor), thus adjusting the levels of its lipase and esterase activities.…”