Investigation of Wheat Germ and Oil Characteristics with Regard to Different Stabilization Techniques

Pozadina istraživanja. Upotreba pšeničnih klica i njihovog ulja ograničena je zbog velike aktivnosti enzima u klicama i prisutnosti nezasićenih masnih kiselina u ulju, što zahtijeva primjenu stabilizacijskih tehnika. Eksperimentalni pristup. U ovom su istraživanju procijenjeni učinci metoda stabilizacije (suho zagrijavanje u konvekcijskoj pećnici na 90 i 160 °C, mikrovalno zračenje na 180 i 360 W i uparavanje u autoklavu) na pšenične klice i njihovo ulje. Rezultati i zaključci. Uparavanje je prouzročilo najdramatičnije promjene aktivnosti lipoksigenaze, udjela slobodnih masnih kiselina, aktivnosti uklanjanja radikala DPPH i masenih udjela tokoferola i tokotrienola. Niži peroksidni broj izmjeren je u uzorcima ulja obrađenim konvekcijskim zagrijavanjem (160 °C) i parom na temperaturama iznad 100 °C. Međutim, vrijednosti p-anisidina u uzorcima tretiranim na višim temperaturama bile su znatno veće od onih u uzorcima stabiliziranim pri nižim temperaturama. Zagrijavanje u pećnici na 160 °C je nakon uparavanja bilo jedno od najučinkovitijih postupaka za inaktivaciju lipoksigenaze. Primjena pare bitno je smanjila maseni udjel ukupnih tokoferola, što je izravno povezano s povećanim gubitkom β-tokoferola. Suprotno tome, pronađeno je znatno više γ- i δ-tokoferola te homologa tokotrienola u uparenim uzorcima. Izomeri najotporniji na procese stabilizacije bili su α-tokoferol i γ-tokotrienol. Novina i znanstveni doprinos. Ovo istraživanje pokazuje da metoda zagrijavanja u pećnici na visokoj temperaturi, koja se često koristi u industriji za toplinsku stabilizaciju pšeničnih klica, ne poboljšava njihovu oksidacijsku stabilnost u usporedbi s obradom parom i mikrovalovima. Uparavanje odgađa oksidacijske procese u klici te inhibira aktivnost lipoksigenaze, a osim toga smanjuje gubitak tokotrienola. Za industrijsku se primjenu preporučuje uporaba mikrovalne pećnice male snage (180 umjesto 360 W) i zagrijavanje u pećnici na nižoj temperaturi (90 umjesto 160 °C).Research background. Utilization of wheat germ and wheat germ oil is limited due to high enzymatic activity and the presence of unsaturated fatty acids, which require stabilization techniques to overcome this problem. Experimental approach. In this study, the effects of stabilization methods (dry convective oven heating at 90 and 160 °C, microwave radiation at 180 and 360 W, and autoclave steaming) on both wheat germ and its oil were evaluated. Results and conclusions. Steaming caused the most dramatic changes in lipoxygenase activity, free fatty acid content, DPPH radical scavenging activity, and mass fractions of tocopherols and tocotrienols. Lower peroxide values were measured in the oil samples treated with convectional heating (160 °C) and steaming at temperatures above 100 °C. However, p-anisidine values of samples treated at higher temperatures were considerably greater than those of samples stabilized at lower temperatures. Oven heating at 160 °C was also one of the most effective treatments, after steaming, for the inactivation of lipoxygenase. Steaming significantly reduced mass fraction of total tocopherols, which was directly associated with the greater loss of β-tocopherol content. On the contrary, γ- and δ-tocopherol and tocotrienol homologues were abundant with higher amounts in steamed samples. α-Tocopherol and γ-tocotrienol were the most resistant isomers to stabilization processes. Novelty and scientific contribution. This study shows that the high temperature oven heating method, which is widely used in the industry for thermal stabilization of wheat germ, does not provide an advantage in oxidative stability compared to steaming and microwave applications. Steaming delayed oxidation in the germ, while further inhibiting lipoxygenase activity. Moreover, tocotrienols were more conservable. In industrial application, low-power microwave (180 instead of 360 W) and oven heating at lower temperature (90 instead of 160 °C) would be preferable

Curative Chemoradiotherapy of Primary Pancreatic Lymphoma with Vertebral Metastasis: Palliation of Persistent Biliary Stricture by Roux-en-Y Hepaticojejunostomy

Primary pancreatic lymphoma (PPL) is a rare tumor that usually presents with the clinical picture of advanced adenocarcinoma but has a much better prognosis. A 38-year-old man was referred after percutaneous transhepatic external biliary drainage for obstructive jaundice. Abdominal magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography had revealed a 5-cm pancreatic head mass that caused biliary tract dilation. Computed tomography angiography showed that the mass encased the celiac trunk as well as the common hepatic and splenic arteries. MRI also revealed a metastatic lesion at the third lumbar vertebra. Serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels were within normal range. The initial diagnosis was inoperable pancreatic adenocarcinoma; however, Tru-Cut pancreatic biopsy showed a large B cell lymphoma. After 6 sessions of chemotherapy and 21 sessions of radiotherapy, both the pancreatic mass and the vertebral metastasis had disappeared. However, he had persistent distal common bile duct stricture that could not be negotiated by either the endoscopic or percutaneous route. A Roux-en-Y hepaticojejunostomy was performed. The patient stayed alive without recurrence for 52 months after the initial diagnosis and 45 months after completion of oncologic treatment. In conclusion, a large pancreatic mass with grossly involved peripancreatic lymph nodes, without ascites, liver or splenic metastasis, should alert the clinician to the possibility of PPL. Cure is possible by chemoradiotherapy even in the presence of vertebral metastasis. Persistent stricture in the distal common bile duct may require a biliodigestive anastomosis