不同包装对山核桃脂肪氧化的影响（简报）

为了选择合适的包装措施以减缓山核桃仁中油脂在贮藏期间的氧化酸败,延长其贮藏期,研究了用聚乙烯塑料膜（Polyethylene,PE）和聚乙烯塑料铝箔膜（Polyethylene/Al,PE/Al）的普通包装与PE、PE/Al的真空包装,4种不同包装措施对山核桃贮藏过程中油脂氧化的影响。通过不同包装对山核桃油脂的酸价、碘价、过氧化值、p-茴香胺值和脂肪氧合酶活性在贮藏过程中的变化情况的影响,确定适合山核桃的包装形式。试验结果表明PE/Al真空包装能有效减缓山核桃油脂的氧化进程,从而延缓山核桃的品质的下降,延长其货架期。     

Lipid analysis of three special nervonic acid resources in China

Nervonic acid plays an important role in nutrition and function of the human body. Malania oleifera, Acer truncatum and Xanthoceras sorbifolium are China’s unique woody plant rich in nervonic acid in seed oil. This study aims to investigate the lipid composition of these 3 special resources. Their fatty acids were detected by gas chromatography coupled with flame detector (GC-FID). Triglycerides (TAGs) and phospholipids (PLs) were detected by shotgun-mass spectrometry (shotgun-MS). Results showed that M. oleifera oil presented the highest level of nervonic acid (46.20 ​± ​0.22%) among the 3 oils. Seeds oil of A. truncatum and X. sorbifolium had 3.53 ​± ​0.20% and 1.83 ​± ​0.21% nervonic acid respectively. 53 species of TAGs and 15 species of PLs were identified in M. oleifera oil, with PLs content of 499.94 ​± ​22.34 ​μg/g. In A. truncatum oil, PL and TAG species were twice more than those in M. oleifera oil, and its’ content of PLs was 76.27 ​± ​3.21 ​μg/g. In X. sorbifolium oil, 75 TAGs and 34 ​PLs were detected, with the lowest PLs at 23.84 ​± ​0.17 ​μg/g. The results demonstrated that these 3 vegetable oils have great potential to become nervonic acid supplements for human health.     

Effect of storage temperatures and duration on quality of prepared chicken breast with paprika oleoresin

The objective of this study was to investigate the effect of storage temperatures and time on discoloration and oxidation of prepared chicken breast with paprika oleoresin. Freshly prepared chicken breast containing paprika oleoresin was stored at ?2, ?10, ?18°C, and an oscillating temperature between ?10 and ?18°C (?10/?18°C). A significant decrease in redness was detected at ?2, ?10, and ?10/?18°C. The lowest TBARS values and carbonyl contents were observed in the samples stored at ?18°C for 5 weeks. Also, the values of sulfhydryl groups gradually decreased with the increase in storage temperatures and duration. The results suggest a positive correlation between the loss of redness and oxidation in all samples. The findings indicated that the discoloration and oxidation of prepared chicken breast added with paprika oleoresin were inhibited significantly when stored at ?18°C.     

Fabrication of olive leaf extract and hazelnut skin incorporated films to improve the quality of nuggets during refrigerated and deep freeze storage

ABSTRACT

1. Olive leaf extract (OLE) and hazelnut skin (HS), which are known to have good antioxidant activity, were added into chicken nuggets in different ways. In the first method, the nuggets were coated with sodium alginate-calcium chloride-based coatings containing OLE and HS. In the second method, OLE and HS were directly added into the nugget patties. Nuggets that did not contain any additive (C1) and the samples prepared with the coating solution that did not include any additives (C2) were assigned as controls.

2. Nuggets were stored at two different temperatures, either in a refrigerator (4°C) or in a deep freezer (?18°C) for 21 days and 90 days respectively. Moisture content (%), pH, antioxidant status (TBARS), colour and microbial count (total mesophilic and psychrophilic aerobic bacteria) analyses were carried out during storage.

3. At the end of refrigerator storage (day 21), TBARS values for samples in which OLE and HS were directly added were found to be lower than those with OLE and HS coatings (P < 0.05). Total number of mesophilic and psychrophilic bacteria were found to be the lowest in the treatment in which HS was directly incorporated into nugget patty (P < 0.05).

4. For frozen samples, application of a coating containing OLE and HS and direct addition of HS into patties were found to be effective in reducing lipid oxidation. No microbial growth was determined in most of the samples stored in the deep freezer.     

Dietary inclusion of dehydrated bocaiuva pulp increases the antioxidant potential of quail eggs

The aim of this study was to evaluate dietary supplementation of different levels of dehydrated bocaiuva pulp (DBP) on the productive performance of laying quails, and on lipid oxidation, and quality in their eggs. A total of 120 quails were distributed in a completely randomized design with six treatments (0%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% of DBP), five replicates and four birds per experimental unit. To evaluate lipid oxidation, the eggs were collected on five consecutive days at the end of the trial and distributed in a completely randomized experimental design in a 6 × 5 factorial scheme (eggs from quails fed different levels of DBP × evaluated fresh and after 7, 14, 21 and 28 days). The antioxidant potential of diets was improved (p < 0.05) when the DBP was added estimated as 2,2'‐azinobis‐3‐ethylbenzothiazolin‐6‐sulfonic acid (ABTS) free radical scavenging capacity. No effect (p > 0.05) was observed on feed intake, hen‐day egg production and feed conversion (kg/kg and kg/dz). There were no changes (p > 0.05) in the egg weight, Haugh unit, yolk index or eggshell percentage. Although no difference was observed (p > 0.05), when comparing each level with the control, a negative linear effect (p < 0.05) on specific gravity was observed. In addition, only the treatment with 0.5% pulp exhibited lower (p < 0.05) eggshell thickness compared with the control (0%). Thiobarbituric acid reactive substances (TBARS) analysis showed that as the dietary pulp level was increased, malondialdehyde content decreased linearly (p < 0.05) in the egg yolks, regardless of the storage period. Inclusion of DBP in the diets had no effect (p > 0.05) on the concentration of conjugated dienes in the eggs. The diets containing DBP showed a potential antioxidant effect, reducing the degree of lipid oxidation in egg yolk. However, no beneficial effects were observed on performance and egg quality.     

花生荚果发育过程中子叶贮藏细胞的形态变化及其与油分和蛋白质积累的关系

花生荚果发育过程中,子叶贮藏细胞的形态和结构皆发生一系列明显的变化。果针入土0-30天,子叶贮藏细胞不断形成分化,体积变化较小,细胞中脂体和蛋白体形成少,而造粉体则形成较多,并大量积累淀粉粒。果针入土30-45天,子叶贮藏细胞迅速生长,脂体、蛋白体大量形成和增大,充满整个细胞。而淀粉粒形成少。果针入土45-68天,子叶细胞生长减慢,脂体则进一步发育,蛋白体持续形成和增大,60天以后蛋白体趋于解体,间质充挤于脂体间隙。未期,子叶细胞停止膨大,并可能因失水而体积略有减小。结果表明,花生子叶细胞的生长发育,是种仁和荚果形态发育的基础;种仁油分和蛋白质的积累则是其体内脂体和蛋白体不断形成和发育的结果。     

Short-term effects of nitrogen on methane oxidation in soils

 The short-term effects of N addition on CH₄ oxidation were studied in two soils. Both sites are unfertilized, one has been under long-term arable rotation, the other is a grassland that has been cut for hay for the past 125 years. The sites showed clear differences in their capacity to oxidise CH₄, the arable soil oxidised CH₄ at a rate of 0.013 μg CH₄ kg^–1 h^–1 and the grassland soil approximately an order of magnitude quicker. In both sites the addition of (NH₄)₂SO₄ caused an immediate reduction in the rate of atmospheric CH₄ oxidation approximately in inverse proportion to the amount of NH₄ ⁺ added. The addition of KNO₃ caused no change in the rate of CH₄ oxidation in the arable soil, but in the grassland soil after 9 days the rate of CH₄ oxidation had decreased from 0.22 μg CH₄ kg^–1 h^–1 to 0.13 μg CH₄ kg^–1 h^–1 in soil treated with the equivalent of 192 kg N ha^–1. A ¹⁵N isotopic dilution technique was used to investigate the role of nitrifiers in regulating CH₄ oxidation. The arable soil showed a low rate of gross N mineralisation (0.67 mg N kg^–1 day^–1), but a relatively high proportion of the mineralised N was nitrified. The grassland soil had a high rate of gross N mineralisation (18.28 mg N kg^–1 day^–1), but negligible nitrification activity. It is hypothesised that since there was virtually no nitrification in the grassland soil then CH₄ oxidation at this site must be methanotroph mediated. Received: 31 October 1997     

日粮烟酸水平对肉仔鸡生长及脂肪代谢的影响

AA肉仔鸡240只,设5个处理,各处理在饲喂相同基础日粮条件下,分别添加烟酸0、15、30、60和120mg/kg。当日粮烟酸添加量由0提高到60mg/kg时,血浆胆固醇、β-脂蛋白、甘油三酯和游离脂肪酸含量分别降低15.4%、18.6%、36.1%、和25.9%;肝脂、肌肉总脂及腹脂含量分别降低35.1%、51.4%和28.0%。提高日粮烟酸水平可降低肉仔鸡血浆雌二醇含量和肝脏苹果酸脱氢酶活性,在本试验条件下,肉仔鸡日粮烟酸添加量以60mg/kg为宜。     

低浓度剩余活性污泥调理剂的优选

对城市污水处理厂低浓度剩余活性污泥进行调理剂优选试验,试验结果表明：采用F04440SH对低浓度剩余活性污泥进行调理取得了较好的调理效果。     

不同浓度NH_3对富营养化湖泊水体硝化作用的影响

通过室内培养试验,研究了不同浓度非离子态氨（NH3）条件下富营养化湖泊——太湖梅粱湾水体硝化作用的2个过程,即氨氧化和亚硝酸盐氧化的发生情况。结果表明,在试验设计的NH3浓度范围内,颗粒态氨氧化和自由态氨氧化速率都随着NH3浓度的升高而显著增加,同时在高浓度NH3（0.65和0.85mg/L）下,颗粒态氨氧化速率在总氨氧化速率中所占比例也显著增加。而亚硝酸盐氧化过程的发生却具有明显的阶段性,当NH3浓度从0.05增加到0.15mg/L时,自由态亚硝酸盐氧化速率有一定的降低,但是颗粒态亚硝酸盐氧化速率却显著增加,导致总亚硝酸盐氧化速率也显著上升;当NH3浓度从0.15增加到0.85mg/L,自由态亚硝酸盐氧化速率随着NH3浓度的升高而进一步降低,同时颗粒态亚硝酸盐氧化速率也随着NH3浓度的增加开始显著降低,导致总亚硝酸盐氧化速率急剧降低。