Extra-Cold Storage of Hake and Mackerel Fillets and Mince

Extra-cold storage (?30 and ?40°C) of mackerel (Scomber scombras) mince and fillets showed lower free fatty acid formation. Extra-cold storage (-30°C) of white hake (Urophycti tenuis) fillets produced fish with better quality based on sensory and chemical indices. The colder the storage temperature, the less firm the hake mince and fillets. Ascorbic acid accelerated cohesiveness development of mackerel mince and fillets. Over time, the quality of the hake and mackerel decreased according to sensory and chemical indices. They became tougher and generally more cohesive.     

SOLUBILIZATION OF APPLE POMACE BY EXTRUSION

Apple pomace (AP), a fibrous by-product of apple juice processing, was solubilized by a twin-screw extruder. AP was extruded under 14 different operating conditions, where the process variables are controlled in the following ranges: screw speed, 250–350 rpm; feed rate, 30–40 kg/h; moisture, 20–30%. Water soluble index (WSI) increased linearly with specific mechanical energy (SME). Soluble dietary fiber of extruded AP also increased with SME, which in turn decreased the content of insoluble dietary fiber (IDF). As a result, total dietary fiber (TDF) remained nearly unchanged. Water holding capacity (WHC) remained nearly constant at low SME, but markedly deceased at high SME due to disintegration of cell wall. Gel filtration of WSP exhibited the structural fragmentation of cell wall by extrusion: the higher SME, the higher fragmentation of SME. Ion exchange chromatography of WSP demonstrated that increasing SME resulted in increasing the extractability of free neutral polysaccharides from the cell wall of AP. It was also found that the degradation of AP cell wall by extrusion preferentially occurred at the arabinogalactan sidechains of pectins.     

INHIBITION STUDIES ON BURDOCK POLYPHENYL OXIDASE (PPO) ACTIVITY

The inhibitory effect of 4-hexylresorcinol (HR), ascorbic acid (AA), citric acid (CA), and bisulfites on polyphenol oxidase (PPO) of burdock roots was studied. HR was an effective inhibitor at low concentrations used in this study for crude PPO from root slices. A binary mixture of HR and AA at 1.0% concentration for 5 min achieved more than 90% inhibition of crude PPO. AA also showed high antibrowning activity for the purified PPO comparable to that of bisulfites, whereas its activity was much lower than that of HR in the crude extract. The inhibitory effect of the combined use of inhibitors was overall in the decreasing order of HR+AA, HR+CA and AA+CA, irrespective of the crude PPO or the purified PPO from burdock slices.     

IN VITRO ANTIOXIDANT AND ANTICANCER ACTIVITIES OF EXTRACTS FROM A FERMENTED FOOD

Solvent extracts were prepared from Manda Enzyme®, one of the fermented health foods, and their activities of radical scavenging and cancer cell growth inhibition were evaluated. Manda Enzyme® was extracted with 55% ethanol, and then fractionated into n‐hexane, chloroform, ethyl acetate, methanol‐soluble and methanol‐insoluble fractions. The antioxidant activities were in the order chloroform > ethyl acetate > other fractions and of each fraction were positively related to the amount of total phenolics and the intensity of brown color. The cancer cell growth inhibitory activities were in the order n‐hexane > chloroform > other fractions. Proliferation of HRT‐18, HCT‐48 and HepG2 human cancer cells was inhibited by the treatment of the n‐hexane fraction of Manda Enzyme® at a concentration of 400 μg/mL to the extent of 75, 89 and 90%, respectively. From these results, it is considered that Manda Enzyme® has chemically different ingredients showing strong antioxidant and anticancer activity in vitro.     

Solution of a functional differential equation via delayed unit step functions

A new set of delayed unit step functions (DUSFs) has been defined. Based on the approximations of the delay operators exp (?hs) and exp ( ?αhs) o α  1) respectively by two new operational matrices of DUSFs ore derived. One is the integration matrix which relates DUSFs to their integrals, and the other is the stretch matrix which relates DUSFs to their stretched forms. By the use of these two operational matrices the solutions of a differential equation of the type [ydot] (t)= ay( are obtained in a series of DUSFs. The results obtained may be piecewise-constant or pointwise. Compared with Walsh or block pulse function approaches, the proposed method is simpler in the construction of its operational matrices, and is more amenable to computer programming.     

Feed/Seed比值对好氧生物处理效率的影响

好氧生物反应器的进料物（Feed）是经厌氧作用的消化污泥，而其接种体（Seed）是活性污泥。主要研究了四种Feed／Seed比值（1：0，3：1，1：1和0：1）对好氧生物处理效率的影响。对于Feed／Seed比值为1：0和0：1而言，污泥的TSS和VSS的去除率很低。而另外两种比值的实验结果表明，TSS和VSS的去除率均随Feed／Seed比值的增加而增加。对于Feed／Seed比值为3的生物反应器，28天的TSS和VSS的去除率分别达到了49％和50％。并且TSS和VSS的降解服从一级反应动力学。动力学降解常数（k）也随Feed／Seed比值的增加而增加。而且VSS的去除率略高于TSS。另外，硝化反应的发生导致好氧生物反应器中的硝酸根离子浓度的增加和pH的降低。     

Protection of Menhaden Mince Lipids from Rancidity during Frozen Storage

Several antioxidants as well as vacuum packaging and changes in frozen storage temperatures (-7°C and -20°C) were tested for their effect on the peroxide values and free fatty acids (FFA) of frozen minces from Gulf menhaden, Brevoortia patronus and Atlantic men-haden, Brevoortia tyrannus. Vacuum packaging was the most effective in retarding oxidative rancidity. Storage at -20°C also reduced the oxidation versus -7°C. Ascorbic acid and crythorbic acid had the best antioxidant activity of the additives tested. Tocopherols, rosemary extracts, and tertiary butylhydroquinone (TBHQ) had limited antioxidant activity. Storage at -20°C inhibited hydrolytic rancidity. Neither vaccum packaging nor any of the additives prevented FFA development at -7°C.     

Flavor, Texture, Color, and Hexanal and TBA Values of Frozen Cooked Beef Packaged in Modified Atmosphere

Cooked beef loin slices were packaged with (1) vacuum, (2) 80% N₂ and 20% CO₂ gas mixture, or (3) air and stored at -20°C for 11 wk. Modified packaging of cooked beef improved flavor and odor. After storage and reheating, flavor and aroma of samples in vacuum and N₂/CO₂ packages were more meaty, less warmed-over, less cardboardy, and less oxidized and had lower TBA, less hexanal, and less pentanal than those in air-containing packages. Textural properties of beef were unaffected by packaging treatments. Vacuum-packaged beef slices had higher HunterLab a values than those in N₂/CO₂ and air packages.