水産魚介類の品質および鮮度維持に関する研究

戦後食糧事情の厳しかった時代は魚介類の鮮度判定および保鮮技術に関する研究が多く行われた。その後コールドチェーンの一応の確立によって防腐問題の解決が図られ、鮮度問題は解決されたかにみなされてきたが、一方で品質保持に関して種々な改良がなされ、急速・極低温冷凍技術が発達するとともに、氷温貯蔵技術の進歩がもたらされ、鮮度判定法としても従来のVBN判定からATP関連物質判定へと発展してきた。しかし今日200海里時代に入り、わが国の漁塞が著しい制約を受けるに及んで、水産資源の有限性に対する認識が昂まるとともに、水産資源の有効利用技術の開発が社会的に要請されるようになった。そのため、近時登場した鮮度保持剤を用いた沖締技術および保鮮包装剤について、それらの効果を検討しようとする研究を実施したので、報告する。 試験魚介類として、カキ、エビ、イワシ、サバ、タイ等を用い、天然海水を対照として塩素およびオゾン処理海水、ピチピチ(トーユー)添加海水(PP)、それらとともにゼオミック(シナネンニューセラ)袋(SP)による保鮮効果を細菌数(一般細菌数、大腸菌数、低温細菌数)、K値、およびIMP濃度、さらにパネルテストによって判定を行った。 クロダイを氷蔵した場合、15日迄の官能検査でPPが最高であり、5℃で貯蔵したものではK値およびIMPともSPおよびO3が良く、イワシ、サバではK値およびIMPともPPは対照より優れていた。カキでは氷蔵下で9日迄官能検愛で、殻付きでもPPは対照に勝り、K値からもPPは対照よりも良い結果が得られた。エビではPPがK値、IMPとも最高であり、一般細菌数、低温細菌数からみるとSPが最も優れていた。また官能検査での臭気からPPが最も良い結果を得た。In order to keep the quality and freshness of the fishery products, various treatments were studied on black sea bream (Acanthopagrus schlegeli) and shrimp (Trachypenaeus curvirostris) stored in ice and at 5°C, mackerel (Scomber japonicus) and sardine (Sardinqs melatzosticta) stored at 5°C, and oyster (Crassostrea gigas) in shucked and unshucked forms stored in ice and at 5°C. In general, among the samples packed by usual polyethylene bags, samples treated by 0.34000f modified amino preservating agent (called Pichi-Pichi, PP) have lower K-value and higher IMP content. The ability of PP to suppress the illcreasing rate of K-value (IRK) and to restrain decreasing rate of IMP (DRI) was slightly higher than saturated ozone treatment, higher than chlorinated treatment (0.04 ppm) and control. Samples packed by laminated-Ag-zeolite polyethylene bags (Zeomic) have lower bacterial counts, IRK and DRI than usual one

Toddaculin, Isolated from of <i>Toddalia asiatica</i> (L.) Lam., Inhibited Osteoclastogenesis in RAW 264 Cells and Enhanced Osteoblastogenesis in MC3T3-E1 Cells

<div><p>Osteoporosis with bone loss is widely recognized as a major health problem. Bone homeostasis is maintained by balancing bone formation and bone resorption. The imbalance caused by increased bone resorption over bone formation can lead to various bone-related diseases such as osteoporosis and rheumatoid arthritis. Osteoclasts are the principal cells responsible for bone resorption and the main targets of anti-resorptive therapies. However, excessive inhibition of osteoclast differentiation may lead to inhibition of osteoblast differentiation. Therefore, it is important to screen for new compounds capable of inhibiting bone resorption and enhancing bone formation. <i>Toddalia asiatica</i> (L.) Lam. has been utilized traditionally for medicinal purposes such as the treatment of rheumatism. Currently, the extract is considered to be a good source of pharmacological agents for the treatment of bone-related diseases, but the active compounds have yet to be identified. We investigated whether toddaculin, derived from <i>Toddalia asiatica</i> (L.) Lam., affects both processes by inhibiting bone resorption and enhancing bone formation. Towards this end, we used pre-osteoclastic RAW 264 cells and pre-osteoblastic MC3T3-E1 cells. We found that toddaculin not only inhibited the differentiation of osteoclasts via activation of the NF-κB, ERK 1/2, and p38 MAPK signaling pathways, but it also induced differentiation and mineralization of osteoblasts by regulating differentiation factors. Thus, toddaculin might be beneficial for the prevention and treatment of osteoporosis.</p></div

Primer pairs used for RT-PCR.

<p>Primer pairs used for RT-PCR.</p

Effect of toddaculin on osteoclastogenesis.

<p>Chemical structure of toddaculin (A) and its effect on TRAP activity in RANKL-treated RAW 264 cells (B). Values are expressed as means ± SEM (n = 3). *, <i>P</i> < 0.05 compared with control. Light microscopic analysis of osteoclast formation is shown in (C). Arrows show multi-nucleated cells. Each picture is representative of at least triplicate analyses.</p