减压贮藏对南果梨后熟进程及抗氧化能力的影响

为探究减压贮藏对南果梨后熟进程及抗氧化能力的影响，以商业成熟期的南果梨果实为试验材料，于2 kPa和25 kPa减压条件下贮藏1个月后，在(20±2)℃、101 kPa条件下模拟其后熟过程，并测定其后熟品质和抗氧化能力的变化。结果表明:2 kPa和25 kPa减压条件均能较好地维持南果梨果实品质；第10天和第15天时，各减压处理组的h°均显著高于对照组(P < 0.05)；自第5天起，对照组果肉硬度均显著低于各处理组(P < 0.05)；自第10天起，减压贮藏组的类黄酮含量均显著高于对照组(P < 0.05)；而各处理组的可溶性固形物和可滴定酸含量与对照组无显著差异(P > 0.05)。同时，与对照组相比，各处理组果实的呼吸峰推迟约5 d，且乙烯释放量显著降低(P < 0.05)。此外，至第20天时，各减压处理果实的多酚氧化酶活性仍显著低于对照组(P < 0.05)，而其过氧化物酶活性显著高于对照组(P < 0.05)。其中，(4±2)℃、2 kPa条件下减压贮藏对南果梨果实后熟进程的延缓作用最为明显，且其抗氧化能力得到较好地维持。     

不同压力条件对平菇减压贮藏效果的影响

为探讨不同压力条件对平菇减压贮藏效果的影响,以MAP贮藏为对照,分别探讨了30-40 kPa、50-60 kPa、70-80 kPa三种压力条件对平菇生理生化变化的影响。结果表明:不同压力条件均可在不同程度上抑制平菇的呼吸强度,减缓可溶性蛋白质的降解,降低褐变度的升高及细胞膜相对电导率的增大,而失重率与CK组差异不显著(P>0.05)。其中,在50-60 kPa压力条件下平菇的保鲜效果最佳,显著优于30-40 kPa和70-80 kPa两种压力条件(P<0.05),最佳压力条件下的失重率、褐变度等指标分别如何?。     

真空条件对黄金梨减压储藏效果的影响

为探讨不同减压贮藏条件对黄金梨保鲜效果的影响,以MAP贮藏为对照试验,分别探讨黄金梨在20～30 kPa、40～50 kPa、70～80 kPa 3个真空压力范围内减压贮藏对梨果实生理生化变化的影响。结果表明:不同真空压力组均可在不同程度上降低梨果实贮藏期间呼吸强度、抑制VC含量和果实硬度的下降,而果实失重率与对照组相比差异不显著(P>0.05),其中真空压力为20～30 kPa时,梨果实的贮藏效果明显优于其它两种压力组。     

几种绿色保鲜技术对双孢菇保鲜效果的比较

研究了薄膜气调、涂膜、L-半胱氨酸、真空减压等几种绿色保鲜技术对双孢菇的保鲜效果,以呼吸强度、失重率、Vc含量、细胞膜透性、褐变度、感官品质为考察指标,进行保鲜效果的比较.结果表明,L-半胱氨酸结合气调保鲜能够有效抑制双孢菇贮藏过程中的褐变、降低失重率、减少维生素c、细胞膜透性和感官品质的变化,而涂膜及真空减压处理后结...     

竹汁联合壳聚糖对双孢菇涂膜保鲜效果的影响

用竹汁和壳聚糖混合液处理双孢菇(Agaricus bisporu),以呼吸强度、硬度、白度、维生素C含量及失重率为评定指标,研究复合涂膜对(4±1℃)下贮藏的双孢菇生理和品质的影响。结果表明,壳聚糖中添加竹汁可明显抑制双孢菇呼吸强度的上升,延缓维生素C含量和白度的下降,降低双孢菇贮藏期间的失重率,和对照相比,可将双孢菇的货架期延长到14d以上。     

等离子体活化水喷淋及浸泡处理的生菜采后品质变化分析

目前基于PAW的果蔬采后品质研究主要采用浸泡处理,较少涉及喷淋处理。该文分别采用PAW喷淋和浸泡对生菜进行处理,并研究了处理后生菜表面菌落总数、失重率、颜色、叶绿素及代谢物的变化。结果显示,PAW喷淋和浸泡处理后生菜表面的菌落总数分别下降1.54和2.82 lg CFU/g(P<0.05),并且PAW喷淋较浸泡处理对生菜失重率和叶绿素的影响较小。代谢组分析表明,PAW喷淋处理组的生菜与对照组相比能维持含量更多的黄酮类物质,而PAW浸泡处理组的生菜与对照组相比膜脂代谢活跃。综上,PAW喷淋处理后在贮藏前期可以有效降低生菜表面菌落总数,并且能够在贮藏期间较好地维持生菜品质。     

蘑菇真空预冷后的减压贮藏效果研究

为了探究贮藏压力对蘑菇贮藏效果的影响,以双孢菇和杏鲍菇为实验材料,在设定值为0℃和0.3 k Pa压力下预冷后,在(0±1)℃贮藏温度下减压(0.01、0.03、0.05、0.07、0.09 MPa和0.1 MPa)贮藏,测量了蘑菇贮藏期间的渗透率、失重率、Vc含量和呼吸强度。结果表明,贮藏压力对失重率以及呼吸强度的影响较明显,失重率和呼吸强度都随着贮藏压力的减小而减小,但减压贮藏不能推迟或提前呼吸高峰期,贮藏结束时,0.1 MPa贮藏压力下的蘑菇的失重率和呼吸强度是0.01 MPa贮藏压力下的2.3倍和1.4倍;减压贮藏对Vc含量和渗透率的影响并不明显,不能推迟或提前Vc含量的低谷期和高峰期;当贮藏压力在0.01~0.1 MPa之间时,最佳贮藏压力为0.01 MPa。     

低温减压贮藏对“川中岛”水蜜桃保鲜效果的影响

研究了不同减压贮藏条件(10、50和90 kPa)对"川中岛"水蜜桃在(4±0.5)℃下贮藏的影响。结果表明:减压贮藏能有效地延缓水蜜桃果实品质下降。其中,经50 kPa处理贮藏效果较好,经其处理的果实褐变程度较低,并明显延缓水蜜桃后熟速率,保持了较高的硬度,与常压对照相比,失重率降低了40.00%,腐烂指数减少了87.50%,保持了水蜜桃较佳的感官品质,对保持水蜜桃色泽、香气、味道有显著效果。     

不同减压处理对圣女果贮藏品质的影响

将圣女果分别放在101.3 kPa(常压)、80、50、20 kPa下,每4 d测定相关指标,研究减压处理对圣女果贮藏品质的影响。结果表明:减压处理可降低采后圣女果的失重率、呼吸强度,抑制Vc含量、可滴定酸含量、可溶性固形物含量、原果胶含量的降低,减缓细胞质膜透性、花青苷含量的上升,从而保持了其贮藏期的品质,延缓其衰老速率,其中以50 kPa处理效果佳。     

真空处理对蔬菜减压贮藏保鲜效果的影响

为研究减压贮藏条件对蔬菜保鲜效果的影响,选择鲜切西兰花、生菜、菠菜为试材,考察了在贮藏温度(4±1)℃,真空度为30、50 kPa和常压3种不同贮藏条件下,蔬菜的失重率、VC质量分数、叶绿素质量分数、色泽及感官品质随贮藏期的变化规律。结果显示:减压贮藏的保鲜效果优于常压贮藏,真空减压技术能更有效的降低失重率,延缓叶绿素与VC的分解,改善保鲜效果。减压处理中以30 kPa条件下贮藏保鲜效果最优。     

Nutritional contents of three edible oyster mushrooms grown on two substrates at Haramaya,Ethiopia, and sensory properties of boiled mushroom and mushroom sauce

The effects of wheat and bean straw growing substrates on nutrient contents of three edible oyster mushrooms and sensory properties of two mushroom foods were investigated. Moisture (fresh weight basis), crude protein, fat, fibre, ash, total carbohydrate, Fe, P and Zn (db) were ranged: 85.18–88.86%, 30.04–37.63%, 1.61–2.55%, 9.33–13.29%, 6.83–9.38%, 29.68–32.53%, 4.86–5.66 mg per 100 g, 12.39–15.36 g kg^?1 and 54.61–65.98 mg kg^?1, respectively. Moisture, fat and fibre were significantly (P < 0.01) affected by substrates, species and their interactions. Substrates showed no differences on ash, Fe and P (P > 0.05). Protein content was high for mushrooms grown on bean straw. Pleurotus sajor‐caju grown on bean straw had high protein, ash, Fe and P contents. No significant (P > 0.05) sensory acceptability differences were observed for boiled mushroom and mushroom sauce except colour of boiled mushrooms. In Ethiopia, if mushroom consumption is popularised, the support for food nutrition security is substantial.     

Effect of nanocomposite-based packaging on storage stability of mushrooms (Flammulina velutipes)

In this study, a polyethylene (PE) packaging material that contained nano-Ag, nano-TiO₂, nano-SiO₂, and attapulgite was prepared and its effect on storage stability of mushrooms (Flammulina velutipes) was investigated. The results showed that the nanocomposite-based packaging material (Nano-PM) regulated oxygen and carbon dioxide level, eliminated ethylene and inhibited the growth of microbes, which is a benefit on preservation quality of mushrooms, compared to the normal PE material (Normal-PM). After 14 days of storage, mushroom weight loss, mushroom cap opening, stipe elongation and respiration of Nano-PM stored mushroom were significantly (P < 0.05) inhibited. Furthermore, treatment with the Nano-PM improved the retention of vitamin C, soluble protein, and total soluble solids contents of F. velutipes. The results therefore are promising for the preservation of F. velutipes in order to expand its shelf life and improve its preservation quality by use of this Nano-PM.Industrial relevanceFlammulina velutipes, also named as golden needle mushroom, is one of the most popular edible mushrooms worldwide. Its production and consumption ranked the fourth place among all edible mushrooms in the world. However, fresh golden needle mushrooms are highly perishable. Therefore, preserving freshness of the mushrooms is the main objective of postharvest technology. In the present study, we developed a new type of effective and economic nanoparticle packaging materials and applied it to mushroom preservation. A local company (Jiangsu Tianfeng Biological Technology Co., Ltd) producing mushrooms has started to use this nano-preservation technology during the postharvest transportation and sales. In conjunction with the results of present research, we suggests that nano-composite based packaging materials is a good way for preserving fresh mushrooms and has the potential to be commercialized.     

Utilisation of dried shiitake,black ear and silver ear mushrooms into sorghum biscuits manipulates the predictive glycaemic response in relation to variations in biscuit physical characteristics

The nutritional quality of gluten-free products is important to the health of individuals with coeliac disease. Mushrooms are good sources of vitamins, dietary fibres and proteins, and are a low-calorie option that can be used in gluten-free diets to improve their nutritional value. The effects of incorporating dried mushrooms on the hydration and pasting properties of sorghum flour, as well as the physicochemical characteristics and in vitro glycaemic response of sorghum biscuits were studied. Sorghum flour enriched with mushroom powders exhibited higher water absorption capacity and swelling power compared with the control (P < 0.05). The addition of shiitake (Lentinula edodes) mushroom significantly decreased the pasting viscosities, while the addition of black ear (Auricularia auricula) and silver ear (Tremella fuciformis) mushroom increased viscosity values (P < 0.05). Biscuit diameter, thickness and weight loss were reduced with increasing mushroom powder addition, and the colour parameters of biscuits were affected significantly. Enrichment with shiitake and black ear mushroom increased the hardness of biscuits (P < 0.05). Inclusion of mushroom powders significantly reduced the predicted glycaemic response of sorghum biscuits (P < 0.05). Correlation analysis was conducted to illustrate that hydration dynamics (such as water absorption capacity and swelling power) were negatively correlated with glycaemic response (P < 0.001).     

Effect of vacuum cooling on mushroom browning

The effects of two cooling methods and two storage temperatures on mushroom quality, anatomy and weight loss were compared. Mushroom quality was assessed as a function of cap browning and hyphal structure. Storage of mushrooms at 5°C conserved quality and reduced weight loss as compared with those stored at 18°C. No differences in quality or hyphal structure were found between vacuum and conventionally cooled mushrooms when subsequently held at 5°C; when cool storage was followed by a period at 18°C, vacuum-cooled mushrooms were significantly better with regard to colour (enzymic browning) than those conventionally cooled. The rate of weight loss during storage at 5°C was greater for vacuum-cooled than conventionally cooled mushrooms.     

减压和1-MCP处理对蓝莓保鲜效果的影响

为探究减压保鲜和1-MCP在蓝莓保鲜上的应用,以东北"灿烂"蓝莓为试材,常压冷藏(4±1)℃为对照,3种处理:在(4±1)℃条件下,1.5k Pa减压处理21d;减压预处理12h;1-MCP处理,并常压冷藏至21d,探究4种处理的感官和生理指标的变化情况。结果表明:与对照比较,3种不同处理方式均能不同程度降低蓝莓的失重率和腐烂率,1.5k Pa预处理12h保鲜效果最好,其次是1-MCP处理,均优于超低压保鲜。相关性分析表明,蓝莓的腐烂率与失重率、呼吸强度呈正相关,而与TSS、总酚、黄酮、花青素等的含量及防御性酶SOD、CAT活性呈负相关。     

OHMIC BLANCHING of MUSHROOMS

Mushrooms that are to be canned are typically blanched for long times to preshrink them. Our objectives were to compare the weight and volume loss of mushrooms during blanching under conventional and ohmic heating conditions and to investigate waveform and frequency effects of ohmic heating. In our setup, it was possible to heat mushroom caps with ohmic heating to above 70C in 40 s while maintaining a 50% solid mushroom content in water. Weight loss predicted using previously published kinetic models, and internal mushroom temperature data suggested that substantially greater shrinkage occurred than attributable to temperature alone. Shrinkage predictions were more consistent with experimental values when the temperature of the surrounding medium was used as a basis, suggesting that some combination of thermal and nonthermal permeabilization mechanisms may be in action. Ohmic blanching offers the advantage of being able to maintain a high solids content during blanching compared to the use of excessive amounts of water (60 kg/400 L) in conventional blanching. Frequency and waveform did not affect the weight loss during ohmic blanching in the range studied. Ohmic heating may have potential for this application due to its rapid, volumetric heating rates, and the enhancement of mass transfer even at relatively low temperatures.     

Sensory and microbiological quality of shiitake mushrooms in modified‐atmosphere packages

The aim of the present work was to study the influence of modified‐atmosphere packaging on the microbiological and sensory quality of shiitake mushrooms (Lentinula edodes). Mushrooms were packaged under atmospheric air (passive modified atmosphere) and an initial gas mixture of 5% O₂ and 2.5% CO₂ (active modified atmosphere), in bags of two different films: low‐density polyethylene (PE) and polypropylene (PP). As control, mushrooms were packaged in macroperforated PP films. Bags were stored at 5 °C for 20 days. Package atmosphere composition, mushroom respiration rate, weight loss, microbiological counts and sensory quality were determined during storage. Risk assays were also performed. Under the studied conditions, shiitake mushroom deterioration was not due to microorganism growth, and therefore the shelf‐life of this product might be defined by changes in its sensory characteristics. Sensory analysis showed that mushrooms stored under modified atmosphere (active and passive) had a higher deterioration rate than those stored in PP macroperforated films, and lower sensory quality values during the entire storage time. These results suggest that mushroom deterioration was probably due to shiitake mushrooms' sensitivity to high CO₂ concentrations. Copyright © 2007 Society of Chemical Industry