• Korean Journal of Food Science and Technology
• /
• v.27 no.6
• /
• pp.964-971
• /
• 1995

Volatile flavor compounds and free amino acids in untreated and hydrolysate pen shell by-product produced with APL 440 protease were compared by vacuum simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry. A total of 109 volatile flavor compounds were detected in hydrolysate (65 compounds) or the 109 volatile flavor compounds were detected in untreated pen shell by-product (88). These compounds were composed of aldehydes(16), ketones(17), alcohols(31), nitrogen containing compounds (16), aromatic hydrocarbon compounds(8), esters(3), and miscellaneous compounds (17). Levels of aldehydes and aromatic hydrocarbons decreased after hydrolysis, whereas levels of nitrogen containing compounds increased 3 times than in untreated pen shell by-product. Taurine, known to be having a physiological function, was accounted for 31.25% of total amino acids in hydrolysate.

• Korean Journal of Food Science and Technology
• /
• v.27 no.6
• /
• pp.958-963
• /
• 1995

The hydrolysis of pen shell by-product by the APL $440^{TM}$, selected as the suitable alkaline protease on the basis of cost per unit enzyme activity, was optimized using response surface methodology(RSM). A model equation obtained from the results of RSM could be used for the prediction of degree of hydrolysis(DH) as follows: $%DH=51.126+2.419\;pH+2.415T-2.426S-2.846pH^2-4.211T^2-3.014t^2+2.419S^2$. From the ridge analysis, the conditions favoring the highest degree of hydrolysis were pH 10.2, $61.4^{\circ}C$, 2.58 hrs reaction time, 30.9% substrate concentration, and 0.32% enzyme/substrate ratio. The effect of autolysis affecting degree of hydrolysis in pen shell by-product was negligible. Hydrolysate produced under the optimal condition increased 3.5 times and 7.7 times in amino nitrogen and salinity, respectively, comparing with raw pen shell by-product.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.5
• /
• pp.509-514
• /
• 1994

A processing method for fermented paste of favorable flavor and texture using pen shell by-product was investigated. The pen shell by-product was homogenized with the addition of water and hydrolyzed with $5\%$ of Protin P(105 PU/g) at $55^{\circ}C$ for 1 hour. Flavor of the hydrolysate could be improved by thermal treatment at $100^{\circ}C$ for 40 minutes with $10\%$ of invert sugar. $2\%$ of agar-agar and $6\%$ of starch added to hydrolysate emulsified by $8\%$ of polyglycerol condensed ricinoleate(PGDR) were significantly effective for the improvement of rheological properties such as hardness, springiness and chewiness of the fermented paste. $15\%$ of table salt was finally added to the product of fermented pen shell paste. The contents of moisture, protein, lipid, carbohydrate and salinity of the product were $62.7\%,\;3.2\%,\;4.4\%,\;10.6\%\;and\;15.6\%$, respectively. The major free amino acids were glutamic acid, arginine, aspartic acid, leucine, lysine, glycine and alanine. The product was stable for the storage of 60 days at $23{\pm}3^{\circ}C$ on bacterial growth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.3
• /
• pp.259-264
• /
• 1994

The possibility of shellfish utilization of juice as seasoning materials was examined through the analyzing proximate compositions and N-containing materials. The amounts of the sucking liquid wastes were estimated as 58,819 tons for oyster, 764 tons for pen-shell, 604 tons for cockle and 3,896 tons for blue-mussel from 1985 to 1990 in Korea. Water contents ranged from 95.2 to $97.4\%$ and crude protein level was $1.0{\sim}1.4\%$. Taurine was the most abundant nitrogenous compound($40{\sim}56\%$) in extracts, and glycine($10.4{\sim}36.1\%$), alanine($4.8{\sim}8.6\%$) and glutamic acid($3.1{\sim}5.3\%$) followed. More than $40\%$ of ADP and AMP as mucleotide were contained in all shellfish samples but pen-shell and cockle had $20\%$ of inosine, also. Glycinebetaine was present in corcentrations of 139.8mg/g in oyster and $45.5{\sim}61.9mg/100g$ in pen-shell, cockle and blue-mussel. Total creatinine and trimethylamine oxide levels were $30.4{\sim}59.1mg/100g$ and $0.82{\sim}47.2mg/100g$, respectively.