超高压对鲜榨果蔬汁的杀菌效果

为防止鲜榨果蔬汁受微生物污染而腐败变质,通过超高压加工处理降低其污染的风险,延长产品货架期,提高产品的安全性。该文通过研究超高压处理鲜榨苹果汁和胡萝卜汁及其在贮藏期的菌落总数变化,确定超高压杀菌后的鲜榨苹果汁和胡萝卜汁的生物安全性。试验结果表明：超高压对低pH值的鲜榨苹果汁的杀菌效果优于pH值偏中性的鲜榨胡萝卜汁。随着处理压力的增大和处理时间的延长,鲜榨苹果汁和胡萝卜汁中的菌落总数显著降低（P＜0.05）。经过400 MPa、15 min处理的鲜榨苹果汁可在4℃下贮藏7 d仍保持食用安全性,而鲜榨胡萝卜汁经400 MPa、45 min处理,仅能在4℃下贮藏3d。     

高静压加工对黄桃罐头品质的影响（英）

为拓展非热加工技术在水果罐头加工中应用,以黄桃罐头为试材,研究了高静压加工对黄桃罐头品质的影响。分析了黄桃罐头果肉或汤汁的质地、显微结构、色泽、pH值、可滴定酸和可溶性固形物在加工前后变化,并与传统热加工产品进行比较。结果表明：高静压加工（600 MPa, >5 min）能有效地保持产品质地、显微结构、色泽、pH值、可滴定酸和可溶性固形物,而热加工（90±2°C, 20 min）导致果肉质地软化、显微结构破坏及可溶性固形物增加,严重影响产品品质。同时感官分析表明,与对照相比,高静压加工黄桃罐头除新鲜度及滋味稍差外,其他方面均无明显差别,而热处理黄桃罐头除保持较好色泽与香气外,其他方面均产生劣质的影响。所得研究结果将为高静压技术在水果罐头中工业化应用提供理论依据。     

超高压处理对卤制鹅胗灭菌保鲜与品质的影响

为了揭示超高压处理对卤制鹅胗灭菌保鲜与品质的影响,以100、200、300、400、500、600 MPa的压力对卤制鹅胗进行处理,保压15 min,以未经高压处理的样品为对照,室温(20±5)℃存放至第1、5、9 天测定样品的菌落总数、大肠杆菌及沙门氏菌等微生物指标,同时对样品的pH值、嫩度、色差等理化指标以及感官指标进行分析。结果表明：400 MPa以上压力保压15 min可以有效抑制大肠杆菌和沙门氏菌的生长;200～500 MPa处理对pH值的影响不显著（P＞0.05）,在9 d存放期中,pH值整体呈下降趋势,鹅胗样品中心点pH值高于边缘部位;超高压处理对嫩度没有显著影响（P＞0.05）;超高压处理对表面色差有显著影响（P＜0.05）。从感官上分析,高压处理对卤制鹅胗的口感、气味及质地等感官品质影响不显著。超高压处理不仅具有较好的杀菌效果,而且最大限度地保证了卤制鹅胗的品质。     

薄膜气调包装对枇杷果实冷藏期间呼吸和品质性状的影响

通过对呼吸速率、总可溶性固形物、可滴定酸、pH值、果肉硬度、维生素C、失重率和品质及感官指标的变化进行分析，研究了薄膜气调包装对枇杷(Eriobotrya japonica Lindl.，品种：解放钟）果实冷藏期间呼吸和品质特性的影响，气调包装用的薄膜为低密度聚乙烯薄膜(LDPE，厚度20 μm)，以打孔的低密度聚乙烯薄膜包装为对照。结果表明，低密度聚乙烯薄膜包装枇杷果实后，3～4 d后可维持一个相对稳定的适宜枇杷贮藏的O₂和CO₂的气体浓度，即CO₂(4.8±0.67)%，O₂(11.5±0.85)%；薄膜气调包装结合低温可明显地降低枇杷果实的呼吸速率；薄膜气调包装可以最大限度地减小冷藏期间的枇杷果实的失重率、果肉硬度、维生素C、总可溶性固形物、可滴定酸和固酸比的变化，维持枇杷的新鲜品质，延长货架期。因此，低密度聚乙烯薄膜（LDPE，厚度20 μm）气调包装可用于枇杷的贮藏保鲜。     

Effects of olive fruit quality and oil storage practices on the diacylglycerol content of virgin olive oils

The evolution of 1,3- and 1,2-isomers of diacylglycerols (DGs) in olive oils obtained from healthy olives and the influence of the olive quality was studied. Healthy olive fruits yielded oils containing almost exclusively 1,2-isomers whereas altered olives produced oils with significant amounts of 1,3-isomers. Virgin olive oils obtained from various olive cultivars and stored at different temperatures showed triacylglycerol hydrolysis and diacylglycerol isomerization depending on the acidity and temperature. The results indicated that the relationship between acidity and total diacylglycerol content has scarce utility for detecting mild refined oil in virgin olive oil. On the other hand, the 1,3-/1,2-DG isomers ratio is useful for assessing the genuineness of virgin olive oils with low acidities during the early stages of storage.     

Effects of high hydrostatic pressure on some functional and nutritional properties of soy protein isolate for infant formula

The effects and mechanism of high hydrostatic pressure (HHP) on some functional and nutritional properties of soy protein isolate (SPI) for infant formula were investigated. Results indicated that solubility, water holding capacity, emulsification activity index, and foaming capacity were improved at lower pressure and time levels, whereas these properties declined at higher levels. However, the emulsification stability index dropped when the pressure increased and the foaming stability decreased with pressure and time levels rising. HHP-treated SPI gave better swallowing properties and in vitro digestibility than control. The hardness, adhesive force, and springiness of SPI gels increased with increaded pressure and elongated time, being lower than those of the control. Near UV circular dichroism spectra confirmed the alteration of tertiary and/or quaternary conformations caused by HHP. Sodiumdoecyl sulfate polyacrylamide gel electrophoresis results indicated that β-conglycinin was more pressure labile than glycinin, and high molecular weight subunits formed via disulfide linkage at higher treatment levels.     

食品工程用超高压设备的设计及性能试验

为了提高超高压设备的稳定性和处理效率,促进超高压技术应用于食品加工,该文阐述了HHP-700-400L型食品工程用大型超高压设备的工作原理、设计要求、主体结构和工作过程,分析并确定了双向水介质增压器、直推式容器堵头及其密封系统、承压容器材料和结构等相关参数。设备单体容积为100L,总容积为400L;最高工作压力为600MPa;处理能力达到1.68t/h。经性能试验表明:设备性能稳定、操作方便、安全可靠。研究结果为大型商业化超高压设备的设计和制造提供参考。     

超高静压下食品压致升温规律的研究

为了弄清食品在超高静压下的压致升温规律,以便准确控制杀菌的加工工艺条件,通过聚四氟乙烯套筒模拟较小热损失条件下,将温度探头伸入高压腔内在线测定了液态食品和固态食品在超高静压下的温度变化情况,研究得出其在不同条件下的压致升温规律。结果表明：在室温下100～400 MPa范围内,脂肪含量高的食品的压致升温值明显高于含水率高的食品的压致升温值,且都随压力的增加而减小。在25～55℃和200 MPa时脂肪含量高的食品压致升温值随初始温度的增加而减小,而水的压制升温值受初始温度影响较大且随初始温度的增加而增加。可见,食品压致升温值主要受其成分的影响。故在食品的超高静压杀菌过程中必须考虑不同食品的压致升温值及热效应问题,以便合理确定食品的超高静压加工工艺条件。     

超声辅助萌芽联合超高压处理对花生-黑豆芽复合汁品质的影响

为有效提高豆种的萌芽特性、明确其生长过程中营养成分变化规律,并对萌芽产品进行绿色深加工以最大限度保留豆芽营养成分,该论文采用超声波处理提高豆类发芽率和发芽指数,筛选营养丰富的萌芽阶段开发花生-黑豆芽复合汁,并研究超高压和常规热杀菌对花生-黑豆芽复合汁品质的影响。结果表明：300 W和10 min的超声处理可显著提高黑豆和花生的发芽率和发芽指数（P<0.05）。超声处理组的黑豆在第6萌芽阶段（芽长6 cm）时γ-氨基丁酸（gamma-aminobutyric acid,GABA）含量最高,达175.13mg/100g,超声处理组的花生在第5萌芽阶段（芽长2cm）时白藜芦醇含量较高,为0.92 mg/g。以上述阶段原料制备富含白藜芦醇和GABA的花生-黑豆芽复合汁,进一步研究发现,相比于传统热杀菌,超高压杀菌（450MPa和15min）可显著提高花生-黑豆芽复合汁的稳定性和总酚含量（P<0.05）,减少颜色劣变,贮藏过程中能更好地保持GABA和白藜芦醇。研究结果将为高品质豆芽深加工产品探索提供理论依据和技术支撑。     

减压贮藏对冷藏枇杷果实品质和木质化败坏的影响

为阐明低温减压贮藏对枇杷果实品质和木质化败坏的影响,该研究应用40～50 kPa压力于(0±0.5)℃下贮藏果实49 d,并每隔7 d测定果实的营养品质、出汁率、硬度、褐变指数、呼吸速率、乙烯产生速率、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)等木质化相关酶活性及木质素含量的变化.结果表明,减压处理可明显抑制冷藏枇杷果实的呼吸强度、乙烯产生和果实褐变,并保持较高的果实可溶性固形物、可滴定酸度和维生素C含量,抑制贮藏21 d后果实硬度的增加,减轻出汁率的下降,降低POD和PAL酶活性的上升趋势,抑制木质素含量的增加.另外,减压贮藏减轻冷藏枇杷果实的木质化败坏,可能与抑制POD和PAL酶活性有关.低温减压贮藏可有效保持果实食用品质,延长贮藏期,是适合枇杷果实贮藏的有效方法.     

减压贮藏对冷藏枇杷果实品质和木质化败坏的影响(英)

为阐明低温减压贮藏对枇杷果实品质和木质化败坏的影响,该研究应用40～50 kPa压力于（0±0.5）℃下贮藏果实49 d,并每隔7 d测定果实的营养品质、出汁率、硬度、褐变指数、呼吸速率、乙烯产生速率、过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）等木质化相关酶活性及木质素含量的变化。结果表明,减压处理可明显抑制冷藏枇杷果实的呼吸强度、乙烯产生和果实褐变,并保持较高的果实可溶性固形物、可滴定酸度和维生素C含量,抑制贮藏21 d后果实硬度的增加,减轻出汁率的下降,降低POD和PAL酶活性的上升趋势,抑制木质素含量的增加。另外,减压贮藏减轻冷藏枇杷果实的木质化败坏,可能与抑制POD和PAL酶活性有关。低温减压贮藏可有效保持果实食用品质,延长贮藏期,是适合枇杷果实贮藏的有效方法。     

The effect of high hydrostatic pressure on the strawberry anthocyanins

Color stability of fruit juice made from strawberries (Fragaria x ananassa, cv. Elsanta) that were subjected to high hydrostatic pressure was studied by measuring the anthocyanin content. High hysrostatic pressure is a method of preservation of food alternative to heat treatment. It is therefore essential to assess the impact of high pressure on color molecules. Samples were pressurized under 200, 400, 600, and 800 MPa for 15 min at a temperature controlled between 18 and 22 degrees C. After application of pressure, the anthocyanin content of the strawberry juice was analyzed by HPLC-UV using a novel isocratic elution system. The high-pressure treated samples were kept at refrigerator temperature (4 degrees C), room temperature (20 degrees C), and 30 degrees C. Two pigments were identified and quantified: pelargonidin 3-glucoside and pelargonidin 3-rutinoside. The highest stability of the anthocyanins was found when strawberries were stored at a temperature of 4 degrees C. High-pressure treatment at 800 MPa led to the lowest losses, at 4 degrees C.     

精准温度控制对枸杞鲜果贮藏品质和香气成分的影响

为研究精准温控技术在枸杞鲜果保鲜中的应用效果,将枸杞分别装入泡沫箱（Control Check,CK）、泡沫箱+蓄冷剂（冰温）和精准温控箱+蓄冷剂（相温）中,记录箱内温度,结合贮藏期间枸杞的品质变化,通过主成分分析法对3组枸杞进行综合评价,并对不同处理香气成分进行分析。结果表明,精准温度控制后箱体内部温度更低,且温度波动保持在0.1 ℃以内,CK组、冰温组、相温组枸杞出现发霉腐烂现象的时间分别为10、20、40 d;贮藏40 d后,相温组枸杞的腐烂率为4.11%,远低于CK组的14.85%,色差低于3,亮度达34.12,可溶性固形物含量、可滴定酸含量、维生素C含量、类胡萝卜素含量分别较CK组高0.65个百分点、0.03个百分点、4.34 mg/100g、2.90 mg/g,相温组枸杞有效抑制腐烂率和失重率的增加,延缓色差的升高和亮度的降低,保持较高的可溶性固形物、可滴定酸、维生素C和类胡萝卜素含量,经主成分得分分析后得到3组枸杞的品质排序为相温组、冰温组、CK组,且精准温度控制贮藏的枸杞醛类、萜类等有利香气成分相对含量更高。因此,精准温度控制技术有利于枸杞鲜果的冷藏保鲜,其中相温贮藏效果更好。研究结果为枸杞鲜果精准温控保鲜提供参考。     

Protective effect of ascorbic acid against the browning developed in apple fruit treated with high hydrostatic pressure.

Apple Reineta variety was used as an apple dessert. The 1-1.5-cm cubes were immersed in a sucrose solution (30% w/v) and subjected to high pressure (HP) of 400 MPa for 30 min at 5 degrees C. Different ascorbic acid concentrations were used to protect the fruit from the browning developed after the HP treatment. After 2 months of storage at 5 degrees C, no brown color was observed in the samples treated with 20 mM ascorbic acid, and they were acceptable to consumers. However, untreated samples presented fermentation, and they were not acceptable to consumers. The electric conductivity and potassium content were found to be good indicators of the metabolites released from the fruit to the solution in samples treated with high pressure. HP did not affect the peroxidase activity but eliminated the microbial population.     

超高压处理对南美白对虾在冷藏过程中贮藏特性的影响

该文以不同的超高压条件(200,400,600,700MPa)对南美白对虾进行处理,通过考察与比较不同压力处理组冷藏过程中感官、微生物以及各化学指标的变化情况,揭示超高压技术对南美白对虾冷藏特性的影响。结果表明:超高压处理可以有效地杀灭南美白对虾中绝大多数微生物,抑制贮藏过程中挥发性盐基氮的积累,延缓pH值的变化,从而延长南美白对虾的货架期,且处理压力越高延长效果越显著;超高压处理会给鲜虾带来不同程度上的煮熟虾的风味;400MPa和600MPa处理使虾在冷藏过程的黑变提前,而700MPa处理可以完全抑制南美白对虾黑变现象的发生;超高压能够改变腺苷三磷酸(ATP)及其代谢产物的代谢情况,但不影响腺苷酸(AMP)的代谢途径。因此超高压处理可以改善南美白对虾在冷藏过程中的品质,对南美白对虾冷藏具有潜在的应用价值。     

Effects of high hydrostatic pressure treatments on biogenic amine contents in goat cheeses during ripening

The application of high-pressure treatment to accelerate cheese ripening may influence the occurrence and profile of biogenic amines. In some cases, high-pressure treatment could yield high amine content, whereas in others the amine concentrations were comparable with those in nontreated ones. Tyramine was the most affected amine. However, the influence of high pressure depended on the treatment applied. The highest amine concentrations were observed when 50 MPa for 72 h was applied, and in which, the content of tyramine was almost three times higher than in the untreated samples. On the contrary, when 400 MPa for 5 min or 400 MPa for 5 min plus 50 MPa for 72 h were applied contents of this amine were similar or lower than those found in control cheeses showing similar degrees of proteolysis. The higher proteolysis, induced by the pressurization treatments, was not correlated with the higher amine production.     

Effects of heat and high hydrostatic pressure treatments on disulfide bonding interchanges among the proteins in skim milk

Traditionally, milk has been heat treated to control microorganisms and to alter its functionality, for example, to increase its heat stability. Pressure treatment has been considered as a possible alternative for microorganism control, but some of the functionality-related milk protein interactions have not been explored. The present study used two novel two-dimensional polyacrylamide gel electrophoresis (2D PAGE) methods to explore the differences in the irreversible disulfide bond changes among the milk proteins after four common heat treatments and after 30-min pressure treatments of milk at 200, 400, 600, and 800 MPa at ambient temperature (22 degrees C). The pasteurizing heat treatment (72 degrees C for 15 s) denatured and aggregated only a few minor whey proteins, but the high heat treatments (100 degrees C for 120 s, 120 degrees C for 120 s, and 140 degrees C for 5 s) formed disulfide-bonded aggregates that included a high proportion of all of the whey proteins and kappa-casein (kappa-CN) and a proportion of the alpha(s2)-CN. Pressure treatment of milk at 200 MPa caused beta-lactoglobulin (beta-LG) to form disulfide-bonded dimers and incorporated beta-LG into aggregates, probably disulfide-bonded to kappa-CN. The other whey proteins appeared to be less affected at 200 MPa for 30 min. In contrast, pressure treatment at 800 MPa incorporated beta-LG and most of the minor whey proteins, as well as kappa-CN and much of the alpha(s2)-CN, into aggregates. The accessibility of alpha(s2)-CN and formation of complexes involving alpha(s2)-CN, kappa-CN, and whey proteins in the pressure treated milk is an important novel finding. However, only some of the alpha-lactalbumin was denatured or incorporated into the large aggregates. These and other results show that the differences between the stabilities of the proteins and the accessibilities of the disulfide bonds of the proteins at high temperature or pressure affect the formation pathways that give the differences among the resultant aggregates, the sizes of the aggregates, and the product functionalities.     

外源硒对芒果硒含量及果实营养品质的影响

探讨叶面喷施和土施外源硒对芒果叶片和果实硒含量、果实矿质元素含量及营养品质的影响,以期为富硒芒果的安全生产提供理论依据和技术支持。以“桂热 82号”芒果为试材,叶面喷施以亚硒酸钠为硒源,设置0.0、25.0、50.0、100.0、150.0和 200.0 mg/L 6个浓度水平,于生理落果结束后,每 15 d喷施一次,连喷 2次。土施设置亚硒酸钠处理和硒酸钠处理,施肥量为 10 g/株,于花期沟施。结果表明,芒果叶片和果实中的硒含量随着叶面喷硒浓度的增加而递增。叶面喷施 50 mg/L亚硒酸钠可显著提高果实 Vc含量,200 mg/L亚硒酸钠可显著提高果实K、可滴定酸含量,100～ 200 mg/L亚硒酸钠可显著降低果实Zn、Ca含量。土施相同量的亚硒酸钠和硒酸钠均可显著提高芒果叶片和果实硒含量。土施硒酸钠叶片和果实硒含量显著高于亚硒酸钠。土施 10 g/株亚硒酸钠显著降低果实 Ca、Mg含量,土施 10 g/株硒酸钠显著提高果实 K、Vc含量,降低果实 Ca含量。叶面喷硒和土壤施硒均可显著提高芒果叶片和果实硒含量,其中叶面喷硒提高幅度远大于土壤施硒提高幅度。土施硒酸钠比亚硒酸钠更容易被芒果吸收。富硒芒果生产上推荐叶面喷施 25.0～ 50.0 mg/L亚硒酸钠,或者土施 10 g/株硒酸钠。     

Effects of thermal processing and storage on available lysine and furfural compounds contents of infant formulas

The Maillard reaction-related effects that thermal treatments during the manufacturing process and storage (at 20 and 37 degrees C) have on powdered adapted and follow-up milk-based infant formulas were estimated by measuring the available lysine and furfural compounds contents of raw cow milk used in manufacturing, intermediate products and formulas. A fluorimetric method was used to measure the available lysine contents, and free and total furfural compounds were determined by HPLC. Statistically significant losses in available lysine (about 20%) in the infant formulas with respect to raw milk were found. The storage period did not affect the available lysine contents of adapted formulas but reduced (16%) the contents of the follow-up ones (from 6.61 to 5.33 g/100 g of protein). No furfural compounds were detected in raw milk, and free and total furyl methyl ketone (FMC) and methylfurfural (MF) were not observed in the analyzed samples. After 6 months of storage, an increase in free hydroxymethylfurfural (HMF) (from 0.34 to 0.77 mg/100 g of protein) and furfural (F) (from nondetectable to 0.1 mg/100 g of protein) in adapted formulas and free HMF (from 1.84 to 2.62 mg/100 g of protein) in follow-up formulas was observed.     

Relationships between leaf and fruit minerals and fruit quality attributes of apples grown under northern conditions

Field experiments were conducted during 1994–1995 in seven apple (Malus spp.) orchards located in the southwest of Finland (the mainland and the Åland Islands). The cultivars were ‘Transparente Blanche’, ‘Samo’, ‘Melba’, ‘Raike’, ‘Red Atlas’, ‘Åkerö’, ‘Aroma’, and ‘Lobo’. Leaf samples from branches bearing fruits (BF) and not‐bearing fruits (BNF) were collected two times during the growing seasons. Fruit samples were picked about one week before commercial maturity. Macronutrient concentrations in fruits and leaves, fruit diameter and juice pH, titratable acidity (TA) and soluble solids concentrations (SSC) were determined. Leaf nitrogen (N), phosphorus (P), and potassium (K) were higher, but calcium (Ca) and magnesium (Mg) were lower in BNF. Branch types (BF and BNF) were closely related in leaf N, P, and Ca, but not in leaf K and Mg at the first sampling time. Fruit N, P, K, and Mg were closely related to each other but not to fruit Ca. Mean fruit N and Ca and leaf P and Mg were low compared with the recommended levels. Relationships between fruit and leaf nutrient concentrations were found only in P and Mg. Fruit diameter increased and juice SSC decreased with increasing leaf N concentration. Fruit P declined with increasing fruit diameter and juice TA increased and SSC/TA decreased with increasing leaf P and Ca concentrations.