SPME Technique for Analyzing Headspace Volatiles in FishMiso, a Japanese Fish Meat-Based Fermented Product

Abstract

The optimized conditions were evaluated for solidphase microextraction (SPME) to investigate the headspace volatiles in fish miso, a Japanese fish meat-based fermented product. The influence on the efficiency for microextraction of such parameters as the sample size, isolation time and temperature, sensitivity and selectivity of several SPME fibers of different liquid phases as well as several extraction techniques was evaluated. Suitable reproducibility and sensitivity of SPME were achieved by combining carbowax/divenylbenzene of 65 m thickness as the liquid phase of SPME, 3 g of fish miso, 40 C of isolation temperature and 40 min of isolation time. The headspace volatiles of fish miso prepared from spotted mackerel were analyzed under the optimized conditions. Although several volatiles contributed to fish miso, certain volatile esters might have played the greatest role in imparting the sweetfruity aroma to the product.Key words: fermented fish paste; solid phase microextraction (SPME); optimization; volatile compounds; calibrationThe increased variety of different value-added and novel products from foreign and domestic food manufacturers has bought a new challenge to food technologists to modify or invent new generic products that fulfill consumers' demand in Japan. One promising product is a fermented fish meat paste, so-called fish miso. Our previous investigations have revealed its nutritional and taste aspects.1,2) However, characterizing the volatiles and standardizing the volatile analysis for this newly developed flavor-rich food product have not previously been carried out. The volatiles are normally present at low concentrations of mgl À1 or less and should therefore be determined by such sensitive analytical techniques as gas chromatography (GC) with flame ionization detection (FID), mass spectrometry (MS) or olfactrometry (O).3) Several techniques requiring preconcentration are usually used, the most traditional and common technique being liquid-liquid extraction. 4)However, these methods are time-consuming, expensive and likely to introduce artifacts resulting from the sample preparation and solvent interaction steps. Moreover they cannot represent the total composition of volatile chemicals in equilibrium as found in the intact aroma. The sample preparation technique should preferably be fast, easy to use, inexpensive and compatible with a range of analytical instruments. Solid-phase microextraction (SPME) is a method that approaches these ideals and is applied to the analysis of various aroma and flavor compounds in a sample. The main advantages of SPME are its simplicity, speed, solventfreedom, high sensitivity, small sample volume, relatively low cost and simple automation.5) Many studies on the application of SPME have been reported for fermented products, including wine, 6) fermented pickled cucumber 7) and fermented vegetable kimchi.8) It has been used to determine a wide variety of volatile compounds in wine, for example esters and alcohols, 9) sulfur compounds, 10) and chlorophenols res...

Volatile components and sensory characteristics of Thai traditional fermented shrimp pastes during fermentation periods

“…Volatile components were extracted and analyzed using modified method from Giri et al (2010). Three grams of each Kapi sample were weighted and transferred to a 20-mL headspace vial with a polytetrafluoroethylene/silicone liner sealed tightly with an aluminium cap (Supelco, Bellefonte, PA, USA).…”

“…These compounds contribute in many flavors and aromas of various foods including fermented products e.g. fish miso, fish paste, shrimp paste, fermented soybean paste and vegetarian soybean paste (Cha and Cadwallader 1995;Giri et al 2010;Wittanalai et al 2011). The formation of pyrazines has been reported to associate with the Maillard reaction through the Strecker degradation as various nitrogen sources including amino acids as a precursor (Nursten 2005) and metabolic activities of microorganisms during fermentation (Labuda 2009).…”

“…Moreover, the activity of aminopeptidase from Tetragenococcus halophilus, found in Indonesian 'Terasi' shrimp paste (Kobayashi et al 2003) and fish sauce, was closely related to the formation of these volatile compounds (Udomsil et al 2010). In addition, 3-methylbutanal has been reported to be originated from the Strecker degradation of certain amino acids (Giri et al 2010). Benzaldehyde (peak no.…”

“…However, SDE requires several steps to extract and concentrate volatile compounds. It is time-consuming and expensive with requiring a large amount of sample (Giri et al 2010). Solid-phase microextraction (SPME) is a potential sample preparation technique because it is easy to use, inexpensive and compatible with a range of analytical instruments.…”

“…Moreover, it is simplicity, speed, solvent-free, high sensitivity, small sample volume, relatively low cost and simple automation (Vas and Vékey 2004). Reports on the application of SPME for volatile compounds analysis in various fermented foods include fish miso (Giri et al 2010), dry-fermented sausages (Marco et al 2004) and vegetarian soybean kapi (Wittanalai et al 2011), but fermented shrimp paste has not been revealed. Therefore, the goal of the present study was to investigate the changes in volatile components of the natural fermented shrimp pastes by GC-MS with the SPME technique as well as their sensory attributes.…”