Flavor characteristics of garlic fish cakes using electronic nose and tongue analyses

This study investigated the utility of garlic powder as a functional ingredient. The aim was to develop fish cakes with improved functionality and sensory preference based on the antioxidant activity and quality characteristics. Increasing amounts of garlic powder in the prepared fish cakes were associated with increasing total polyphenol and flavonoid contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS+) radical scavenging activity, and reducing power. Furthermore, electronic tongue and electronic nose analyses showed an increased the intensity of umami and sourness and increased the levels of volatile compounds. The lowest trimethylamine peak corresponded to the highest amount of garlic powder. Sensory evaluation indicated that 3% garlic powder had the highest score for all criteria. Fishy odor decreased as the proportion of garlic powder increased. These findings suggest that the addition of 3% garlic powder improves quality characteristics, sensory preference, and antioxidant activity of fish cakes.

Impact of steaming pretreatment process on characteristics and antioxidant activities of black garlic (Allium sativum L.)

Impact of steaming pretreatment processes on physical properties, bioactive compounds and antioxidant activities, of black garlics (Allium sativum L.) was studied. Steaming pretreatment at different times (0, 4 and 6 min) was conducted before incubating in 60 °C-incubator at different incubation times (0, 9 and 18 days). Different steaming pretreatment processes affected the color and hardness of black garlic differently, while total polyphenol content (TPC) and total flavonoid content (TFC) were also determined by the steaming pretreatment time used. TPC and TFC increased with increasing of incubating time, where the highest those bioactive compounds was observed from 18-day incubation, especially with 4 min of steaming pretreatment (p ≤ 0.05). Increase of those bioactive compounds was in accordance with increasing of DPPH radical scavenging activity (DPPH) and ferric reducing antioxidant power (FRAP) of black garlic during incubation. In addition, black garlic obtained from 18-day incubation with steaming pretreated for 4 min revealed the optimum condition providing the black garlic with high in both DPPH and FRAP, compared with others (p ≤ 0.05). Therefore, steaming pretreatment could effectively improve the efficiency of black garlic production process by increase the generation rate of bioactive compounds as well as induce antioxidant properties of black garlic with shorten process time.

Improving the quality of vegetable foodstuffs by microwave inactivation

With the aim of improving the loss of quality in retorted vegetables, experiments on pretreatment inactivation using microwaves were carried out to allow the heating intensity to be reduced during retorting. Microwave heating reduced the bacteria level by 10³ CFU/g, and was a more effective method considering the short processing time of 3 min and the required energy being 70-80% of that when using steam. The inactivation effect was due to dielectric heat generation by the high-frequency microwaves. The inactivation effect for heat-resistant Bacillus amyloliquefaciens was indicated by a reduction of 10² CFU/g after 3 min of microwave heating. The total bacteria counts for peeled potato and spicy sauce with vegetables decreased by 3-4 log CFU/g after 3 min using microwaves, and heat-resistant microorganisms were reduced by 2 log CFU/g. Combining microwave heating and mild retorting is expected to produce higher quality vegetable foodstuffs compared to conventional retorting.