Respiration and quality responses of sweet cherry to different atmospheres during cold storage and shipping

Most sweet cherries produced in the US Pacific Northwest and shipped to distant markets are often in storage and transit for over 3 weeks. The objectives of this research were to study the effects of sweet cherry storage O₂ and CO₂ concentrations on the respiratory physiology and the efficacy of modified atmosphere packaging (MAP) on extending shelf life. Oxygen depletion and CO₂ formation by ‘Bing’ and ‘Sweetheart’ cherry fruit were measured. While respiration rate was inhibited linearly by reduced O₂ concentration from 21% to 3–4% at 20 °C, it was affected very little from 21% to ∼10% but declined logarithmically from ∼10% to ∼1% at 0 °C. Estimated fermentation induction points determined by a specific increased respiratory quotient were less than 1% and 3–4% O₂ for both cultivars at 0 and 20 °C, respectively. ‘Bing’ and ‘Sweetheart’ cherry fruits were packaged (∼8 kg/box) in 5 different commercial MAP box liners and a standard macro-perforated polyethylene box liner (as control) and stored at 0 °C for 6 weeks. MAP liners that equilibrated with atmospheres of 1.8–8.0% O₂ + 7.3–10.3% CO₂ reduced fruit respiration rate, maintained higher titratable acidity (TA) and flavor compared to control fruit after 4 and 6 weeks of cold storage. In contrast, MAP liners that equilibrated with atmospheres of 9.9–14.4% O₂ + 5.7–12.9% CO₂ had little effect on inhibiting respiration rate and TA loss and maintaining flavor during cold storage. All five MAP liners maintained higher fruit firmness (FF) compared to control fruit after 6 weeks of cold storage. In conclusion, storage atmospheres of 1.8–14.4% O₂ + 5.7–12.9% CO₂ generated by commercial MAP, maintained higher FF, but only the MAP with lower O₂ permeability (i.e., equilibrated at 1.8–8.0% O₂) maintained flavor of sweet cherries compared to the standard macro-perforated liners at 0 °C. MAP with appropriate gas permeability (i.e., equilibrated at 5–8% O₂ at 0 °C) may be suitable for commercial application to maintain flavor without damaging the fruit through fermentation, even if temperature fluctuations, common in commercial storage and shipping, do occur.     

肥料种类对不同采收期‘黄金梨’糖酸含量和风味的影响

【目的】为优化肥料类型组合和用量、确定果实品质最佳的采收期,【方法】以5年生‘黄金梨’为材料,应用田间试验方法,研究了5种肥料类型对不同采收期‘黄金梨’果实糖、有机酸组分含量和风味的影响。【结果】结果表明,施用堆肥+叶片喷施氨基酸肥或腐熟动物废弃料可显著提高果实总糖、蔗糖、果糖和葡萄糖含量,降低总酸及苹果酸、酒石酸含量,而施用鸡粪+草炭或堆肥+生物菌肥与单施农家堆肥相比效果不明显。采样期间(9月14日—10月10日),不同肥料类型处理‘黄金梨’果实总糖和果糖、蔗糖、葡萄糖含量及风味指数均先增加后降低,总酸和苹果酸、酒石酸含量则先降低后增加,9月28日采样时总糖及各糖分含量最高,总酸及有机酸组分含量最低,糖酸比和风味指数最大,且以堆肥+叶片喷施氨基酸肥或腐熟动物废弃料两个处理效果最好。【结论】综合分析,‘黄金梨’施用堆肥+叶片喷施氨基酸肥或腐熟动物废弃料有利于提高果实内在品质和风味;9月28日左右是北京地区黄金梨果实采收的最适时期。     

程度相似度评价烟用香精质量

采用气相色谱/质谱法（GC/MS）建立烟用香精指纹图谱,计算并比较12种烟用香精6批次样品、稀释品和掺兑品的夹角余弦、相关系数和程度相似度。结果表明,程度相似度算法可较好的反映样品间的质量差异。     

Analysis of Mount Atlas mastic smoke: A potential food preservative

Pistacia terebinthus L. smoke has been used traditionally in Iran as disinfectant and air purifier. Smoke was collected by a simple method, and the chemical constituents and antimicrobial activity of the smoke were analyzed. The chemical constituents of the smoke were α-pinene (65.1%), limonene (11.5%) and allo-ocimene (2.8%). The non polar phase of smoke noticeably inhibited the growth of different microorganisms. MIC test shows that non polar fraction of smoke can inhibit the growth of some bacteria. The results indicating that the properties of the smoke as a flavoring and preservative agent could be a potential subject for future studies.     

气质联用检测沉香燃烟粒相物中的挥发性成分

利用气质联用对沉香燃烟粒相物中的挥发性化合物进行定性及半定量检测,并对萃取溶剂、溶剂用量、振荡时间进行优化。最终选定二氯甲烷为萃取溶剂,溶剂用量为30 m L,振荡时间为30 min;对人工沉香和天然沉香燃烟粒相物谱图进行了分析,共鉴定出123种物质,主要为一些小分子挥发性物质、降解糖、单萜及含甲氧基的化合物,其中有26种物质具有各种香气特征的常用于食品香料的制备,在天然沉香燃烟中,26种具香气的物质所占鉴定物质总量的百分比高于人工沉香。     

外源性cAMP对秦川犊牛生长性能及部分血液指标的影响

旨在观察外源性cAMP对秦川犊牛生长性能及部分血液指标的影响。选取体质量相近的秦川犊牛公、母各6头(2月龄±10 d)。公母犊牛均分成试验组和对照组,进行120 d的饲养试验,试验组每隔10 d皮下注射cAMP标准注射液10 mL(0.6 mg/kg);对照组注射等量生理盐水。结果表明,和对照组相比,公犊牛末体质量、日增体质量分别提高8.99%、20.00%(P0.01),血清总胆固醇浓度在240 h内降低26.10%(P0.05),血糖浓度、生长激素质量浓度在72 h内分别提高6.50%、8.24%(P0.05),胰岛素质量浓度在48 h内提高7.43%(P0.05)。母犊牛末体质量、日增体质量分别提高7.94%、19.18%(P0.01),血清总胆固醇浓度在240 h内降低12.18%(P0.05),血糖浓度、生长激素质量浓度在72 h内分别提高8.30%、6.72%(P0.05),胰岛素质量浓度在48 h内提高6.15%(P0.05)。由此可知,注射外源性cAMP可显著提高犊牛的生长性能,并影响部分血液生化指标。     

Dietary nucleotides improve the growth performance,antioxidative capacity and intestinal morphology of turbot (Scophthalmus maximus)

A growth trial was conducted to evaluate the effects and safety of nucleotides in low fish meal diets on the growth performance, antioxidative capacity and intestinal morphology of turbot (Scophthalmus maximus). High fish meal control diet was formulated with 500 g kg^?1 fish meal. Seven levels (0.075, 0.15, 0.225, 0.300, 1.5 and 3.0 g kg^?1, respectively) of nucleotides were added to a low fish meal basal diet, which was formulated with 400 g kg^?1 fish meal. The eight experimental diets were fed to groups of juvenile turbot (initial weight: 6.0 ± 0.03 g) for 60 days. Results showed that compared with high fish meal control diet, low fish meal basal diet treatment had lower total antioxidative capacity (T‐AOC), glutathione peroxidase activity, fold height of proximal and distal intestine, enterocyte height of all evaluated enteric section and microvillus height of mid‐intestine and distal intestine (P < 0.05). However, supplemented nucleotides in diets could significantly improve growth (specific growth rate, SGR), feed utilization, antioxidative capacity and intestinal morphology of turbot (P < 0.05). Broken‐line regression analysis of SGR and T‐AOC showed that the optimal supplemental levels of dietary nucleotide for juvenile turbot were 0.366 and 0.188 g kg^?1, respectively. In summary, 0.300 g kg^?1 of dietary nucleotides was helpful in improving growth, feed utilization, antioxidative capacity and intestinal morphology of turbot fed with low fish meal diet. Excessive dietary nucleotides (3.0 g kg^?1) might cause oxidative stress and morphological damage in intestine and then reduce the growth of turbot.     

Effects of dietary nucleotides on growth,survival and metabolic response in whiteleg shrimp,Litopenaeus vannamei against ammonia stress condition

This trial was conducted to evaluate the effects of nucleotides on growth of whiteleg shrimp, Litopenaeus vannamei, and the survival and metabolic responses to ammonia stress test. Experimental diets were as follows: low fish meal diet (LFMD), and four LFMD test diets, each supplemented with 0.1% guanosine monophosphate (GMP), 0.1% inosine monophosphate (IMP), 0.1% mixture of GMP and IMP and 0.1% mixture of GMP, IMP, uridine monophosphate (UMP) and cytidine monophosphate (CMP). The shrimp specimens (initial body weight: 0.99 ± 0.01 g) were randomly allocated into five groups and fed four times daily for 8‐weeks. After the trial, final body weight was recorded and haemolymph was withdrawn for haematological analysis. The shrimp was then challenged with 70 mg/L ammonia (LC50) for 10 days. Survival and haemolymph of the shrimp were taken after exposure to ammonia. The highest growth performance was observed in the shrimp fed diet supplemented with GMP (p < .05), while survival was not influenced by the test diets in the feeding trial. In the ammonia challenge test, the highest survival was observed in the shrimp fed GMP supplemented diet compared to others. The plasma protein, glucose and cholesterol levels increased in all the treatments while triglycerides level decreased post challenge. Cortisol level recovered at day 10th after the challenge. Shrimps fed with nucleotides diets showed higher protein and glucose level compared to control groups post challenge. In general, nucleotides supplemented in the diet enhanced growth, improved stress resistance while modulating the haemolymph metabolites in L. vannamei under ammonia stress.     

苹果品种果实糖,酸含量的分级标准与风味的关系

根据对渤海湾地区129个苹果品种果实可溶性糖、可满足酸含量连续2年测定结果,提出了苹果品种果实糖、酸含量可以分为极高、高、中、低、极低5级及其分级标准。这一分级标准的确定,为苹果果实风味的评价和不同地区果实风味的比较提供了参考依据。根据对苹果果实糖、酸含量的测定和对果实口尝品评的结果,对糖、酸含量与果实风味的关系做了探讨。风味优良的品种,其糖酸比多在20-60的范围,偏高者风味趋甜,偏低者风味偏酸。而糖酸比值小于10的风味均不佳。优质的品种,其果实含酸量多为中等(0.40—0.69％),合酸量极高者风味最差。果实含可溶性糖的变化幅度不大,而含可滴定酸的变幅较大。因此,风味的优劣受含酸量的影响较大。