Gyoon-Woo Lee

Protein functionality of concentrates prepared from yellowfin tuna (Thunnus albacares) roe by cook-dried process

Three kinds of roe protein concentrates (RPCs: boil-dried concentrate, BDC; steam-dried concentrate, SDC; freeze-dried concentrate, FDC) were prepared from yellowfin tuna to produce value added products for food applications. The buffer capacities of the RPCs were higher under alkaline than under acidic conditions. The water holding capacities of the RPCs were in range 4.5–4.7 g/g protein at pH 6.0. The protein solubility of the FDC (14.2%) was higher than those of the BDC (5.4%) and SDC (5.5%) at pH 6.0. The foaming capacity of the FDC (156.8%) was higher than those of the BDC (109.7%) and SDC (109.4%); the FDC foam was stable for 60 min. The oil-in-water emulsifying activity index of the FDC (12.2m2/g protein) exceeded those of the BDC and SDC (2.2m2/g protein). Protein concentrates from yellowfin tuna roe may be useful as a potential protein source and as a high-value food ingredient.

Chemical composition and functional properties of roe concentrates from skipjack tuna (Katsuwonus pelamis) by cook-dried process

Abstract The objective of this study was to investigate physicochemical properties of protein concentrate from skipjack tuna roe by a cook‐dried (boiled or steamed‐dried) process, and to evaluate their food functional properties. The yields of boil‐dried concentrate (BDC) and steam‐dried concentrate (SDC) prepared from skipjack tuna roe were 22.4 for BDC and 24.4% for SDC. Their protein yields were 16.8 and 18.4%, respectively. In terms of major minerals of the BDC and SDC, sulfur (853.2 and 816.6 mg/100 g) exhibited the highest levels followed by potassium, sodium and phosphorus. The prominent amino acids of roe protein concentrates (RPCs) were Glu, Asp, Leu and Val. The BDC and SDC showed a higher buffer capacity than egg white (EW) at the pH‐shift range. The pH‐shift treatment significantly improved the water holding capacities of RPCs, except pH 6. But they had a low solubility across the pH‐shift range. The foaming capacities (104%–119%) of BDC and SDC were significantly lower than those of EW (p < .05), and their foam stabilities were not observed. Emulsifying activity index (m2/g protein) of RPCs and EW was 2.3 for BDC, 11.1 for SDC and 18.0 for EW. RPCs in the food and seafood processing industries will be available as egg white alternative protein sources and will be available as ingredients of surimi‐based products in particular.

Properties of Calcium Lactate Prepared from Calcined Littleneck Clam Ruditapes philippinarum Shell Powder

바지락(Littleneck clam, Ruditapes philippinarum)은 백합목 (Veneroida), 백합과(Veneridae)에 속하며, 그 분포는 한국과 일 본, 중국뿐만 아니라 스페인, 미국 북서부 연안에서도 다량 서 식하고 있는 것으로 알려져 있다(Anderson, 1982). 우리나라 에서 굴, 전복 다음으로 생산 및 소비가 많은 패류로서, 바지락 생산량은 1990년 74,581톤을 정점으로 점차 감소되어, 2013년 에는 18,145톤으로 급격히 감소 하였으나, 이런 추세 속에 바지 락 수입량은 2000년 2,092톤을 시작으로 2014년 35,621톤을 수입하는 등 수입량이 매년 증가하고 있다(Ministry of Ocean and Fisheries, 2015). 수산물 소비 증가에 따라 가공 및 조리 중에 다양한 가공부산 물이 발생하고 있으며, 특히 패류의 경우, 2014년에 419,000톤 정도가 생산 및 수입되어, 육질을 채취하고 버려지는 패각은 생 산량의 50%정도인 연간 209,500톤 정도 발생하는 것으로 추정 된다(Ministry of Ocean and Fisheries, 2015). 지금까지 패각은 토양개량, 비료첨가제, 사료첨가제(Seco et al., 2014; Oliveira et al., 2013), 폐수정화, 수질정화(Kwon et al., 2009) 등 한정된 분야에서 국한적으로 이용되었다. 바지락(Ruditapes philippinarum) 패각 소성분말로 제조한 젖산칼슘의 특성

Characterization of Calcium Lactate Prepared from Butter Clam Saxidomus purpuratus Shell Powder

To facilitate the effective use of butter clam shell as a natural calcium resource, we determined the optimal conditions for calcium lactate (BCCL) preparation with high solubility using response surface methodology (RSM). The polynomial models developed by RSM for pH, solubility and yield were highly effective in describing the relationships between factors (P<0.05). Increased molar ratios of calcined powder (BCCP) from butter clam shell led to reduced solubility, yield, color values and overall quality. The critical values of multiple response optimization to independent variables were 1.75 M and 0.94 M for lactic acid and BCCP, respectively. The actual values (pH 7.23, 97.42% for solubility and 423.22% for yield) under optimization conditions were similar to the predicted values. White indices of BCCLs were in the range of 86.70–90.86. Therefore, organic acid treatment improved color value. The buffering capacity of BCCLs was strong, at pH 2.82 to 3.80, upon the addition of less than 2 mL of 1 N HCl. The calcium content and solubility of BCCLs were 6.2–16.7 g/100 g and 93.6-98.5%, respectively. Fourier transform analysis of infrared spectroscopy data identified BCCL as calcium lactate pentahydrate, and the analysis of microstructure by field emission scanning electron microscopy revealed an irregular form.