ANTIOXIDANT ACTIVITY OF BENE HULL OIL COMPARED WITH SESAME AND RICE BRAN OILS DURING THE FRYING PROCESS OF SUNFLOWER OIL

The antioxidant activity of Bene hull oil (BHO) was compared with that of sesame oil (SEO) and rice bran oil (RBO) during the frying process of sunflower oil (SFO) at 180C. The ratio between the polyunsaturated and saturated fatty acids and calculated oxidizability were statistically greater for the SFO (4.26 and 6.48, respectively), followed by the SEO (3.18 and 6.27, respectively), RBO (1.53 and 4.37, respectively) and BHO (0.37 and 1.67, respectively). Peroxide and acid values of the oils studied ranged from 0.34 to 3.07 mEq/kg and from 0.19 to 5.20 mg/g, respectively. Total tocopherols and phenolics contents of the SEO (1093.28 and 1042.43 mg/kg, respectively) were significantly higher than those of the SFO (740.27 and 38.68 mg/kg, respectively), BHO (573.41 and 276.67 mg/kg, respectively), and RBO (832.98 and 67.98 mg/kg, respectively). In total, based on the conjugated diene value and carbonyl value measurements during the frying process, the BHO showed an antioxidant activity higher than those of the SEO and RBO at the level of 2%, and the levels higher than 2% of the antioxidative oils caused to decrease the oxidative stability of the SFO, indicating the pro-oxidant effect of the oils added at these levels.

PRACTICAL APPLICATIONS

This research introduces the oil obtained from the hull of Bene, a species of pistachio growing wild in Iran, as a new source of vegetable oil for human nutrition with antioxidant activity significantly higher than sesame and rice bran oils, which are considered as very stable and antioxidative vegetable oils because of the presence of very strong indigenous antioxidants, during the frying process.     

Biochemical Study on the Nonprotein Trypsin and Chymotrypsin Inhibitors in the Soybean

The chemical properties of nonprotein trypsin inhibitor (NPTI) and nonprotein chymotrypsin inhibitor (NPCTI) in the soybean were studied. NPTI was extracted with 50% methanol and treated with TCA to a final concentration of 16% (W/V). Two dimensional thin-layer chromatography was used to make a peptide map of the methanol extract; 14 spots were observed. To distinguish the active peptides, the sample was mixed with trypsin or chymotrypsin; some peptides disappeared which formed complexes with the enzyme. The relative rate of inhibition indicated that inhibition was stoichiometric for trypsin and chymotrypsin. Dissociation constants of complexes (enzyme and inhibitor) showed that inhibition of chymotrypsin and trypsin were competitive and uncompetitive, respectively.     

DIFFERENTIAL ACCUMULATION OF THE MOLECULAR FORMS OF POLYGALACTURONASE IN TOMATO MUTANTS

Endopolygalacturonase [poly (1–4-α-D galacturonide) glycanhydrolase, EC 3.2.1.15] activity was measured in samples of cv. Rutgers, Nr (never ripe) and F₁ hybrids of rin (ripening inhibitor, + rin, ++), nor (nonripening, ++, + nor) and rin × nor (+ rin + nor) fruits taken at three day intervals during ripening. Day 1 of ripening was taken as the day on which the first persistent increase in ethylene production was recorded. The enzyme was first detected on day 3 in Rutgers, F₁ rin and F₁ nor, and on day 6 in Nr and F₁ rin × nor. The Rutgers and F₁ rin samples softened more rapidly than the other samples and they also contained more enzyme activity. Enzyme activity developed less rapidly in Nr than in any other samples, but the Nr and the nor hybrid, samples softened at comparable rates. In Rutgers and F₁ rin, a high molecular weight form of the enzyme (PG1, Mr 100 000) predominated to day 6, and a lower molecular weight form (PG2, Mr 43 000 - 46 000) progressively increased after day 6. In all F₁ nor, F₁ rin × nor and Nr samples the enzyme was predominately or entirely as PG1. The interrelationship of PG1 and PG2 and their roles in ripening are discussed.     

EFFECT OF PROCESSING METHOD ON PRODUCTS MADE FROM SWEET POTATO MASH1

Green and cured (seven days at 29°C and 90% RH) ‘Centennial’ sweet potato roots were used to make and evaluate frozen and canned mashes and canned whole roots. Fried patties and pies were made from each of the processed products. The frozen mash from green roots was higher in pH while the canned mash from green and cured roots was lower in pH and higher in viscosity. The canned mash had the lowest ‘L’ and ‘a’ readings but was rated the highest in color score when made into pies. However, the fried patties were scored higher in color when made from frozen mashes or canned whole roots. Moreover, pies made from low viscous mashes were scored low in texture.     

不同参数对热泵性能影响的实验研究

在热泵领域,有许多影响装置性能和效率的参数。本研究采用实验方法研究重要参数对热泵性能的影响。在不同工况下,利用实验室热泵装置研究制冷剂类型和充注量、压缩机油黏度、压缩机冷却风扇、二次流体温度和流量等参数的影响。选择不同的制冷剂作为热泵的循环流体。 本文在研究不同参数对COP的影响之外,还对其经济性进行了分析。结果表明,制冷剂充注量是影响COP的主要参数之一,添加合适的制冷剂可使系统性能提高11%以上。此外,通过选择低黏度压缩机油,系统性能提高18%。当采用冷却风扇冷却压缩机元件时,系统性能提高超过6%。     

铁尾矿陶粒混凝土的制备与性能分析

用铁尾矿陶粒替代普通混凝土天然粗骨料,根据《轻骨料混凝土技术规程》(JGJ/T 12—2019)设计配合比,制备LC30～LC40的铁尾矿陶粒混凝土.测定和计算其力学性能、耐久性、经济性,并与普通混凝土作对比.结果表明,铁尾矿陶粒混凝土能够满足《轻骨料混凝土技术规程》(JGJ/T 12—2019)中LC30配制强度,其...