Determination of Volatiles and Carotenoid Degradation Compounds in Red Pepper Fermented by Lactobacillus parabuchneri.

Red pepper (Capsicum annuum L.) has been used as one of key ingredients in certain fermented foods due to it providing a unique hot and spicy sensation. In this study, volatile compounds-including degradation compounds of carotenoids-in fermented red pepper inoculated with Lactobacillus parabuchneri were investigated. In total, the contents of certain alcohols, benzene and its derivatives, esters, hydrocarbons, lactones, pyrazines, and terpenes were increased in red pepper inoculated with L. parabuchneri, while those of aldehydes, sulfur-containing compounds, and ketones decreased during the fermentation period. The contents of some degradation compounds of carotenoids (ß-ionone, ß-cyclocitral, α-ionone, and ß-damascenone) increased significantly with the fermentation period. In particular, the content of ß-damascenone-which could form by the degradation of neoxanthin-increased gradually during fermentation, but this compound was not detected in 0-day samples. These findings indicate that the contents of certain volatiles-including degradation compounds of carotenoids-in fermented red pepper inoculated with L. parabuchneri can change markedly during the fermentation process. PRACTICAL APPLICATION: This study investigated the changes of volatiles and carotenoids degradation compounds in fermented red pepper inoculated with Lactobacillus parabuchneri during fermentation. These results could be used to improve the quality of red pepper-based products and in the development of certain fermented foods, including Gochujang (fermented red pepper paste) and kimchi.

Purification and biochemical properties of a galactooligosaccharide producing beta-galactosidase from Bullera singularis.

A beta-galactosidase, catalyzing lactose hydrolysis and galactooligosaccharide (GalOS) synthesis from lactose, was extracted from the yeast, Bullera singularis KCTC 7534. The crude enzyme had a high transgalactosylation activity resulting in the oligosaccharide conversion of over 34% using pure lactose and cheese whey permeate as substrates. The enzyme was purified by two chromatographic steps giving 96-fold purification with a yield of 16%. The molecular weight of the purified enzyme (specific activity of 56 U mg(-1)) was approx. 53 000 Da. The hydrolytic activity was the highest at pH 5 and 50 degrees C, and was stable to 45 degrees C for 2 h. Enzyme activity was inhibited by 10 mM Ag3+ and 10 mM SDS. The Km for lactose hydrolysis was 0.58 M and the maximum reaction velocity (V(max)) was 4 mM min(-1). GalOS, including tri- and tetra-saccharides were produced with a conversion yield of 50%, corresponding to 90 g GalOS l(-1) from 180 g lactose l(-1) by the purified enzyme.

Effect of carbon source and aeration rate on broth rheology and fungal morphology during red pigment production by Paecilomyces sinclairii in a batch bioreactor.

The influence of carbon source and aeration rate on fermentation broth rheology, mycelial morphology and red pigment production of Paecilomyces sinclairii was investigated in a 5-l stirred-tank bioreactor. The characteristics of P. sinclairii grown on starch and on sucrose medium were comparatively studied: the specific growth rate in sucrose medium (0.04 h(-1)) was higher than that in starch medium, whereas the specific production rate of red pigments (0.04 gg(-1)d(-1)) was favorable in starch medium. P. sinclairii grown in sucrose medium were highly branched and showed longer hyphal lengths than that in starch medium. The consistency index (K) in sucrose medium was markedly higher than that in starch medium due to higher cell mass, while the higher values of flow behavior index (n) were indicated at the late stationary phase in starch medium. The aeration rate was varied within the ranges from 0.5 to 3.5 vvm while running the fermentation at mild agitation of 150 rpm using sucrose as the carbon source. The maximum biomass concentration of P. sinclairii was about 33 gl(-1) with an aeration rate of 1.5 vvm, whereas the maximum yield of red pigment production (4.73 gl(-1)) was achieved with 3.5 vvm. The highly branched cell morphology appeared at 1.5 vvm and the highly vacuolated cell morphology was observed in a high aeration rate (3.5 vvm). There was no significant variance in rheological parameters (K and n) between culture broths from different aeration conditions.