Effect of different sterilization methods on sensory quality and volatile flavor of flavor crab meat sauce

Flavor crab meat sauce (FCMS) is a new type of aquatic condiment that is not only rich in nutrition but also unique in terms of flavor. However, very little is known about how sterilization methods affect the sensory quality and volatile flavor of FCMS. In the present study, canned FCMS was subjected to the following sterilization methods: pasteurization (PS), microwave sterilization (MS), ultrasonic sterilization (US), and high temperature sterilization (HTS). Each sterilization method was evaluated on the basis of texture, color, sensory score, volatile flavor, and total viable counts in FCMS observed after sterilization. Results demonstrated that the total viable count decreased to 28, 26, 58, and 18 CFU/g respectively after PS, MS, US, and HTS treatments; no coliform group was detected in any of these samples. PS and MS had no significant effect on the texture of FCMS (P > 0.05), but US and HTS reduced hardness and viscosity of FCMS. MS and HTS significantly reduced the L*, a*, and b* values of FCMS (P < 0.05). The original brightness and red value of FCMS remained the same after PS and US. MS and HTS reduced the sensory score of FCMS to a great extent, while PS and US maintained the original sensory score of FCMS. Assessment of volatile flavor profile of FCMS post different sterilization treatments revealed that MS and HTS reduced the total ester content, while US reduced the total amount of alcohols in FCMS. However, PS not only maintained the original total amount of esters in FCMS, but also increased the content of alcohols, aldehydes, and ketones. Therefore, PS could be selected as a feasible sterilization method for FCMS among the four different sterilization methods.

Properties of Biodiesel Purified by Membrane Technology

Membrane technology is the most effective technology in the process of separation and purification because the separation of components can occur to the molecular level. Therefore the application of membrane technology in the biodiesel production process can provide high-purity biodiesel quality. In this research, the process of separating and refining palm oil biodiesel does not use the washing process, but it uses membrane separation technology. The membrane used is the ceramic ultrafiltration membrane 0.02 µm. The purification process was carried out at temperature 70°C and pressure 12 Psi (0.86 bar), flow rate of 39.53 L/min, circulation time of 3 hours with a feed of 10 L. After purification, an obtained biodiesel has physical properties as follows: Purity level 97.63% mass (total ester content) and 97.02% mass (methyl ester content), kinematic viscosity at 40°C is 5.70 (cSt), density 0.86 (g/cm3), acid number 0.45 (mg KOH/g) and the saponification number 206.45 mg KOH/g. The values ​​of the physicochemical properties have met Indonesian National Standard (SNI).

Screening of Mold Producing Aroma in Chinese Koji and Optimization of Culture Conditions

The mold strains with stronger ability producing aroma were screened from 15 mold strains of the laboratory, and the culture conditions were optimized. The result showed: the strains njsys-6, njsys-45, njsys50 had stronger ability producing aroma. In koji juice medium, the strains had the most abundant metabolites, the esterifying enzyme activity and total ester content were the highest for 7.19U/mL and 0.18%. Njsys-45 could resistant high concentration ethanol and temperature up to 10% and 36°C respectively, it could resistant pH3.6. It had been confirmed that njsys-45 strains could be added aroma substances in Koji, and the esterifying enzyme activity was 7.18U/mL, the total ester was 0.18%.

Effects of Aminoethoxyvinylglycine Plus 1-Methylcyclopropene on ‘Royal Gala’ Apple Volatile Production After Cold Storage

Both aminoethoxyvinylglycine (AVG) and 1-methylcyclopropene (1-MCP) are useful tools for managing apple fruit ripening, and their impacts on apple volatile production have been independently assessed. In this work, their combined effect, as might occur in commercial production and postharvest storage, on ‘Royal Gala’ apple volatile production at harvest and after air storage was compared with the effect of each alone. An aqueous solution of AVG was applied to ‘Royal Gala’ apple trees 4 weeks before the normal harvest date (H1) at 124 g·ha−1/a.i. in 2004 and 2005. Control and AVG-treated fruit were treated at H1 or after harvest of AVG fruit 2 weeks later (H2) for 20 h at 30 °C with 1-MCP at a final headspace concentration of 1 μL·L−1. Fruit were ripened for 7 d at room temperature immediately after harvest and treatment or after treatment and then cold storage at 4 °C for 6 or 12 weeks. Peel and cortex tissue of control and AVG plus 1-MCP-treated fruit was provided with butanol or hexanol and ester production was quantified. The combination of AVG plus 1-MCP was more effective in reducing internal ethylene concentration than either alone. Both total volatile production and that of the major individual esters, including hexyl acetate, butyl acetate, and 2-methylbutylacetate, which are considered key constituents of ‘Gala’ aroma, were consistently repressed by the combination of AVG plus 1-MCP after harvest and up to 12 weeks of cold storage. The effects of AVG plus 1-MCP were evident even with H2 fruit when the effects of AVG alone on fruit ripening were at least partially lost. Because alcohol–acyl transferase activity was unaffected by AVG plus 1-MCP, AVG plus 1-MCP-treated peel and cortex samples had similar total ester production when they were provided butanol or hexanol. Total alcohols showed recovery in most treatments except AVG plus 1-MCP, so precursor availability was likely the major factor limiting ester production. The results indicated a sustained adverse effect of the AVG plus 1-MCP treatment on aroma volatile production that could impact consumer acceptability.

(25) Characterization of Volatile Biosynthesis in `Jonagold' Apples (Malus ×domestica Borkh.) during the Ripening Process

The objective of the experiment was to determine developmental changes in major aroma profiles in `Jonagold' apple (Malus ×domestica Borkh.) and analyze climacteric fruit characteristics. Changes in internal ethylene production, respiration, skin color, texture, and aroma concentration were measured during maturation and ripening of `Jonagold' apple fruit. Patterns for skin color, starch, and internal ethylene content were typical for the variety. Volatile compounds and CO2 increased after a rapid increase in ethylene production. Total ester emission peak coincided with fruit softening. Hexyl acetate, 2-methylbutyl acetate, butyl acetate, and hexyl 2-methylbutanoate were found to be the major volatile compounds detected by GC/MS. Long chain esters, such as hexyl acetate and butyl acetate, contributed during the early stages of ripening and short chain esters such as n-propyl acetate and butyl propanoate increased later. Esters are formed by combining alcohol moiety with CoA derivative of fatty acid moiety by the action of alcohol acyl transferase (AAT). The alcohols butanol, 2-methylbutanol, propanol, and hexanol increased at an earlier developmental stage than the esters for which they acted as substrates.