Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii

Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels.     

Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures

This study examined the concentrations of umami compounds in pork loins cooked at 3 different temperatures and 3 different lengths of cooking times. The pork loins were cooked with the sous vide technique. The free amino acids (FAAs), glutamic acid and aspartic acid; the 5′‐nucleotides, inosine‐5′‐monophosphate (IMP) and adenosine‐5′‐monophosphate (AMP); and corresponding nucleoside inosine of the cooked meat and its released juice were determined by high‐performance liquid chromatography. Under the experimental conditions used, the cooking temperature played a more important role than the cooking time in the concentration of the analyzed compounds. The amino acid concentrations in the meat did not remain constant under these experimental conditions. The most notable effect observed was that of the cooking temperature and the higher amino acid concentrations in the released juice of meat cooked at 80 °C compared with 60 and 70 °C. This is most likely due to the heat induced hydrolysis of proteins and peptides releasing water soluble FAAs from the meat into the cooking juice. In this experiment, the cooking time and temperature had no influence on the IMP concentrations observed. However, the AMP concentrations increased with the increasing temperature and time. This suggests that the choice of time and temperature in sous vide cooking affects the nucleotide concentration of pork meat. The Sous vide technique proved to be a good technique to preserve the cooking juice and the results presented here show that cooking juice is rich in umami compounds, which can be used to provide a savory or brothy taste.     

Effects of 3 Feeding Modes on the Volatile and Nonvolatile Compounds in the Edible Tissues of Female Chinese Mitten Crab (Eriocheir sinensis)

To reveal the impact of different feeding modes on the flavor quality of female Chinese mitten crab (Eriocheir sinensis) this study was conducted to compare the sensory evaluation scores, flavor compounds in meat and hepatopancreas of female E. sinensis fed with 3 feeding modes, that is, natural diets (NDs), traditional diets (TDs), and formulated diets (FDs). The result showed that crabs fed with ND had significantly lower sensory scores than the other 2 feeding modes in both edible tissues. The odor and taste profiles were evaluated by Electronic nose (E‐nose) and tongue (E‐tongue) techniques, respectively; results of perchloric acid showed each edible tissue had significant differences among the 3 modes. Contents of volatile compounds were measured by Headspace‐solid phase micro extraction combined with gas chromatography‐mass spectrometer. A total of 35 and 44 volatile compounds were identified in meat and hepatopancreas, respectively. ND mode of meat had the highest relative odor activity value (ROAV) summation among the 3 diet modes. TD mode of hepatopancreas had significantly higher ROAV summations. Based on the analysis of free amino acids and 5′‐nucleotides, nonvolatile compounds were evaluated by equivalent umami concentration (EUC) and taste active values (TAVs) methods. For both meat and hepatopancreas, TD had the highest contents of umami amino acid, as for the 5′‐nucleotide, FD had the highest 5′‐inosin monophosphate concentrations. Overall, the EUC and TAVs of TD were higher than that of FD, whereas ND mode had the lowest values in the 2 edible tissues. In conclusion, TD mode had the best performance in terms of sensory evaluation, ROAVs of aroma‐active compounds, and nonvolatile active compounds.     

Characteristic Flavor of Traditional Soup Made by Stewing Chinese Yellow‐Feather Chickens

The traditional recipe for Chinese chicken soup creates a popular taste of particular umami and aroma. The present study investigated the effects of stewing time (1, 2, and 3 h) on the principal taste‐active and volatile compounds and the overall flavor profile of traditional Chinese chicken soup by measuring the contents of free amino acids (FAAs), 5′‐nucleotides, minerals and volatile compounds and by evaluating the taste and aroma profiles using an electronic nose, an electronic tongue and a human panel. Results showed that the major umami‐related compounds in the chicken soup were inosine 5′‐monophosphate (IMP) and chloride, both of which increased significantly (P < 0.05) during stewing. The taste active values (TAVs) of the equivalent umami concentration (EUC) increased from 4.08 to 9.93 (P < 0.05) after stewing for 3 h. Although the FAA and mineral contents increased significantly (P < 0.05), their TAVs were less than 1. The volatile compounds were mainly hexanal, heptanal, octanal, nonanal, (E)‐2‐nonanal, (E)‐2‐decenal, (E,E)‐2,4‐decadienal, 1‐hexanol, and 2‐pentyl furan. With the prolonged stewing time, the aldehydes first increased and then decreased significantly (P < 0.05), while 1‐hexanol and 2‐pentyl furan increased steadily (P < 0.05). The aroma scores of the chicken soup reached the maximum after stewing for 3 h. The discrepancy in overall flavor characteristics tended to stabilize after 2 h of stewing. In general, stewing time has a positive effect on improving the flavor profiles of chicken soup, especially within the first 2 h.     

热风微波联合干燥过程中南美白对虾滋味物质变化研究

为研究热风微波联合干燥过程中南美白对虾滋味物质的变化,测定了其呈味核苷酸与游离氨基酸含量,同时根据干燥过程中虾肉水分含量计算两者的干基含量变化,并计算虾肉味精当量.研究结果表明:虾肉干燥过程中,呈味核苷酸中肌苷酸含量最高,干制虾肉肌苷酸含量为405.96 mg/100 g,且始终高于阈值,对干制虾肉的鲜味形成有显著贡献;相比鲜样,干制南美白对虾中肌苷酸与单磷酸腺苷干基含量均显著下降;在虾肉中谷氨酸对鲜味形成有显著贡献,甘氨酸、丙氨酸与精氨酸对甜味形成有贡献,苯丙氨酸、赖氨酸与组氨酸能产生苦味;而在干燥过程中鲜、甜味氨基酸相对含量不断上升,分别从3.77％和17.03％上升到4.29％和35.84％;游离氨基酸总干基含量始终下降,但甘氨酸、丙氨酸、精氨酸与脯氨酸4种可以形成良好滋味的游离氨基酸干基含量上升;虾肉中肌原纤维蛋白与肌浆蛋白的干基含量均不断下降,部分分解为游离氨基酸;虾肉味精当量整体呈显著上升趋势,但在微波干燥初期(前40 s)显著下降,干制南美白对虾味精当量为3.50 g/100 g,远高于鲜虾(0.53 g/100 g),且虾肉味精当量始终远高于阈值.研究结果表明,由热风微波联合干燥引起的水分挥发与物质变化能够促进南美白对虾滋味形成.     

Characteristics of functional brown rice prepared by parboiling and microwave drying

Brown rice (BR) is well known for its functional properties; however, it is considered unsuitable for consumption in modern diet owing to its hard texture, low digestibility, and high lipid peroxidation. In this study, we investigated the physicochemical properties, and cooking and storage characteristics of functional BR prepared by parboiling (100°C, 15 min) and microwave drying (100 kW, 8 rpm, 91°C, 40 min) processes. These processes significantly increased resistant starch (RS) content by 1.5-fold and total dietary fiber (TDF) content by 1.8-fold; Parboiling and microwave drying processes increased the umami taste by 10% using electronic tongue and decreased the hardness by 10% using texture analyzer, respectively. Additionally, irrespective of the storage duration, these processes remarkably decreased acidity and bacterial counts in the parboiled BR group compared to that in the BR group. Presumably, higher RS and TDF contents, enhanced umami taste, and longer shelf-life of BR would help patients with obesity and diabetes, and industries developing relevant high-value food products.     

不同蒸制时间下鲟鱼背部肉的滋味特征差异分析

通过仪器分析法对蒸制不同时间鲟鱼肉的非挥发性风味物质进行量化,包括游离氨基酸、风味核苷酸、有机酸、甜菜碱和无机离子;采用电子舌结合感官评价的方法对鲟鱼肉进行滋味分辨和味觉评价,以期为鲟鱼肉热加工过程中的质量控制提供理论参考。结果表明:在蒸制过程中,鲜味氨基酸和甜味氨基酸含量变化明显,在蒸制12 min时显著降低（P<0.05）,蒸制16 min时显著升高（P<0.05）;蒸制不同时间风味核苷酸含量存在差异,蒸制12~16 min时风味核苷酸总量最多,蒸制16 min时IMP+GMP的含量达到最大值;随着蒸制时间的延长,有机酸和无机离子总量在减少,其中乳酸、Na+和PO₄3-损失较为严重;电子舌的主成分分析（PCA）结果显示,鲟鱼肉在蒸制8 min后其滋味变化程度较小;感官评价的结果显示,蒸制16 min的鲟鱼肉具有较好的滋味和较高的整体可接受度。较长时间的蒸制并不会给鱼肉感官带来显著改善,反而会造成味感下降。因此,鲟鱼肉应在蒸制12~16 min内食用,蒸制16 min左右滋味最佳。     

Fatty Acid Content,Flavor Compounds,and Sensory Quality of Pork Loin as Affected by Dietary Supplementation with l‐arginine and Glutamic Acid

To investigate the effect of functional amino acid on meat flavor and eating quality, 60 growing‐finishing pigs (Duroc × Large White × Landrace) were dietarily supplemented with or without 1.0% l ‐arginine, glutamic acid, or l ‐arginine plus glutamic acid for 2 months. After animals were slaughtered, the muscle fatty acid profile, flavor compounds, and meat sensory quality were comparatively investigated. The results showed that dietary supplementation with arginine, glutamic acid, or arginine plus glutamic acid had little effect on free amino acids, no effect on 5′‐nucleotides and meat sensory taste traits, but supplementation with arginine plus glutamic acid significantly increased (P < 0.05) fat accumulation and fatty acid content in muscle, increased (P < 0.05) the formation of multiple fatty acid oxidation‐derived volatile compounds, and improved the tenderness, juiciness, and overall eating quality of meat. This study revealed that dietary supplementation with 1.0% l ‐arginine and glutamic acid could be used to improve meat eating quality in pork production.     

Effects of culture substrates on taste component content and taste quality of Lentinula edodes

In this research, the effects of culture substrates on taste component content of Lentinula edodes were studied, and the resulting taste quality of L. edodes was evaluated. The results revealed that single‐carbon and single‐nitrogen sources were beneficial to production of soluble sugars and polyols, organic acids and sweet amino acids, whereas a single‐carbon source was beneficial to essential amino acid production, and a mixed‐carbon source was beneficial to umami 5′‐nucleotides and high mushroom production yield. High C/N values were beneficial to trehalose, arabitol, malic acid, and succinic acid production, while low C/N values were beneficial to mannitol and citric acid production. L. edodes fruiting bodies, harvested from a culture substrate containing single carbon, high proportion of cereal bran, had a more palatable taste quality, while a substrate containing bagasse and low C/N values was not suitable for L. edodes cultivation due to unfavourable taste quality. These results provide cultivation information how to obtain fruiting bodies L. edodes with more taste components.     

微波熟制对小龙虾营养与风味的影响

目的:探究微波熟制工艺对小龙虾营养成分与风味成分的影响。方法:以鲜活小龙虾为试验对象,分析未经微波加热及210,350 W微波加热5 min后的熟制小龙虾肌肉部分的营养成分与风味成分变化。结果:低功率微波加热并未对小龙虾水分含量造成显著影响,而350 W微波条件下水分损失显著。干基样品中,不同功率微波处理后灰分无显著变化;总糖和粗脂肪含量呈降低趋势;而随着微波功率的提高,粗蛋白含量呈上升趋势。微波熟制对小龙虾不饱和脂肪酸含量有显著影响;总氨基酸及必需氨基酸含量显著下降,但仍保持较高的营养价值。随着微波功率的提高,小龙虾中的风味成分含量显著降低,如呈鲜、甜味的游离氨基酸与呈味核苷酸,其味道强度值及味精当量值均有明显损失。结论:微波加热熟制工艺在一定程度上会使小龙虾肉质营养有所损失,但可以接受;而对于小龙虾的鲜香风味与滋味有明显降低趋势,且微波功率越大,风味损失越多。     

High hydrostatic pressure treatment and storage of carrot and tomato juices: Antioxidant activity and microbial safety

The application of high hydrostatic pressure (HHP) (250 MPa, 35 °C for 15 min) and thermal treatment (80 °C for 1 min) reduced the microbial load of carrot and tomato juices to undetectable levels. Different combinations of HHP did not cause a significant change in the ascorbic acid content of either juice (P > 0.05). Both heat treatments (60 °C for 5–15 min and 80 °C for 1 min) resulted in a significant loss (P < 0.05) in the free‐radical scavenging activity as compared to untreated samples. HHP‐treated juices showed a small loss of antioxidants (below 10%) during storage. The ascorbic acid content of pressurized tomato and carrot juices remained over 70 and 45% after 30 days of storage, respectively. However, heat treatment caused a rapid decrease to 16–20%. Colour changes were minor (ΔE = 10) for pressurised juices but for heat‐pasteurised samples it was more intense and higher as a result of insufficient antioxidant activity. HHP treatment (250 MPa, 35 °C for 15 min) led to a better product with regard to anti‐radical scavenging capacity, ascorbic acid content and sensory properties (colour, pH) of the tomato and carrot juices compared to conventional pasteurisation. Therefore, HHP can be recommended not only for industrial production but also for safe storage of fresh juices, such as tomato and carrot, even at elevated storage temperatures (25 °C). Copyright © 2007 Society of Chemical Industry     

Structural Characteristics of Pumpkin Pectin Extracted by Microwave Heating

Abstract: To improve extraction yield of pumpkin pectin, microwave heating was adopted in this study. Using hot acid extraction, pumpkin pectin yield decreased from 5.7% to 1.0% as pH increased from pH 1.0 to 2.0. At pH 2.5, no pectin was recovered from pumpkin flesh powder. After a pretreatment at pH 1.0 and 25 °C for 1 h, pumpkin powder was microwave‐extracted at 120 °C for 3 min resulting in 10.5% of pectin yield. However, premicrowave treatment at 60 °C for 20 min did not improve extraction yield. When microwave heating at 80 °C for 10 min was applied after premicrowave treatment, final pectin yield increased to 11.3%. When pH was adjusted to 2.0, the yield dropped to 7.7% under the same extraction conditions. Molecular shape and properties as well as chemical composition of pumpkin pectin were significantly affected depending on extraction methods. Galacturonic acid content (51% to 58%) of pumpkin pectin was lower than that detected in commercial acid‐extracted citrus pectin, while higher content of neutral sugars and acetyl esters existed in pumpkin pectin structure. Molecular weight (M_w) and intrinsic viscosity (η_w) determined for microwave‐extracted pumpkin pectins were substantially lower than acid‐extracted pectin, whereas polydispersity was greater. However, microwave‐extracted pectin at pH 2.0 had more than 5 times greater M_w than did the pectin extracted at pH 1.0. The η_w of microwave‐extracted pectin produced at pH 2.0 was almost twice that of other microwave‐extracted pectins, which were comparable to that of acid‐extracted pectin. These results indicate that extraction yield of pumpkin pectin would be improved by microwave extraction and different pectin structure and properties can be obtained compared to acid extraction. Practical Application: Pumpkin is a promising alternative source for pectin material. Pumpkin pectin has a unique chemical structure and physical properties, presumably providing different functional properties compared to conventional commercial pectin sources. Depending on the conditions to produce pumpkin pectin, diverse molecular structures can be obtained and utilized in various food applications.     

Sensory Changes in Umami Taste of Inosine 5'-Monophosphate Solution after Heating

Discrimination in umami taste of inosine 5′-monophosphate (IMP) solution caused by thermal degradation was investigated by sensory evaluation. The difference threshold of umami taste of 0.005% IMP solution in the presence of 0.05% monosodium glutamate (MSG) was 0.002%. The difference threshold of a 0.005% IMP solution decreased by about one half when heated at 95°C for 15 h. Inosine, one of the main products of the thermal degradation of IMP, had a bitter taste. The detection threshold of inosine varied widely among panelists. Heating a 0.005% IMP solution at 95°C for 15 h formed inosine at about one tenth of its lowest detection threshold.     

Effect of temperature–time pretreatments on the texture and microstructure of abalone (Haliotis discus hanai)

The effects of temperature/time pretreatments on the texture and microstructure of abalone (Haliotis discus hanai ) meat with the same myofibril extraction rate (60–66.7%) were investigated. The abalone samples were categorized into control and four treatment groups of different heating temperature/heating time combinations as 50°C/120 min, 60°C/10 min, 70°C/5 min, and 80°C/2 min, respectively. Compared to the control samples, the abalone samples heated at 60°C/10 min were the most tender (minimum shear force). It is clear that a sharp reduction in hardness was observed in heat treated abalone meat samples, compared to the raw samples. Nuclear magnetic resonance (NMR) showed that the water distribution pattern in abalone samples changed as they were experiencing different heat treatments. Particularly, the immobilized water components in samples heated at 60°C/10 min increased significantly. The textural properties of these samples evaluated after an 80 s‐reheating by microwave were of superior quality. It is concluded that the optimal condition for pretreatment abalone was 60°C/10 min, which could significantly improve the textural properties of preprocessed abalones.

Practical applications

Ready‐to‐eat foods can either be consumed directly, or further prepared according to consumers' preference. They are processed and packed following scientifically defined criteria to meet ready‐to‐eat requirements. For consumers, the quality of the food is one of the most important factors affecting purchasing decisions. Pretreatment through heating plays a key role in determining the eating quality of the product. Our study investigated the effects of pretreatment temperature and time on the food quality. These findings will establish optimal conditions for pretreating abalone to develop high‐quality ready‐to‐eat food products.

     

不同生长阶段下中华绒螯蟹滋味成分差异研究

本文比较了8月份到12月份下中华绒螯蟹雄蟹滋味物质间的差异。通过用电子舌区分不同月份下中华绒螯蟹三个可食部位(体肉、性腺、肝胰腺)的滋味轮廓,并测定其游离氨基酸和呈味核苷酸含量,计算TAV值、EUC值,结果表明电子舌能较好区分不同月份下各可食部位滋味轮廓间的差异,11月份、12月份的滋味轮廓与8月份、9月份相比差异较大;三个可食部位中呈甜味氨基酸含量与性腺中呈鲜味氨基酸含量均在11月份达到最高;蟹肉中呈味核苷酸总量最高,且波动较大,11月份以后呈鲜味核苷酸和呈甜味核苷酸含量显著增高,而性腺和肝胰腺中呈味核苷酸含量波动较小;不同阶段下中华绒螯蟹各可食部位的Glu、Ala、Arg和Lys的TAV值均大于1,对蟹的整体滋味贡献较大;性腺中的EUC值显著高于其他部位,并且在9月份、12月份达到最高。综上,雄蟹在11月份滋味最佳。     

Thermal inactivation of Salmonella spp. in ground chicken breast or thigh meat

Thermal inactivation of a four‐strain mixture of Salmonella spp. was determined in chicken breast and thigh meat. Inoculated meat was packaged in bags and then completely immersed in a circulating water bath and held at 55, 57.5, 60 and 62.5 °C for pre‐determined lengths of time. When the surviving bacteria were enumerated on tryptic soya agar supplemented with 0.6% yeast extract and 1% pyruvate (non‐selective medium), D‐values (time to inactivate 90% of bacteria) in chicken breast meat were 6.08, 4.77, 3.00 and 0.66 min at 55, 57.5, 60 and 62.5 °C, respectively; the values in thigh meat ranged from 11.48 min at 55 °C to 0.84 min at 62.5 °C. As expected, the measured heat resistance was lower when the recovery medium was selective (xylose lysine deoxycholate agar). Thermal death time values from this study will assist food processors in designing the HACCP plans to effectively eliminate Salmonella spp. in cooked chicken breast and thigh meat.     

The rheological properties of exudates from cured porcine muscle: effects of added non‐meat proteins

Meat exudates were collected from massaged cured porcine M semimembranosus using a model massaging unit. Exudates were used to observe changes in gelation properties due to the incorporation of commercially available non‐meat proteins. These included: soya isolate (90%), sodium (Na) caseinate (85%) and high gelling whey protein concentrates (WPCs, A‐35%, B‐75% and C‐β‐lactoglobulin (55%), as well as a regular 76% protein, WPC D. Compositional analysis ( n=6) showed that incorporation of non‐meat proteins significantly (P<0.05) increased the protein concentration of test exudates in all cases compared to controls. The viscoelastic properties of control and test meat exudate samples (n=6) were analysed using control stress rheology in oscillatory mode. All exudates were heated from 20 to 80°C at 1°C min⁻¹, and subsequently cooled after 30 min back down to 20°C at 1°C min ⁻¹. Addition of WPCs at a 1, 2 and 3% residual powder level and soya isolate at a 1% residual level, resulted in increased storage modulus G′ (Pa) values compared with controls. A 1% residual level of Na caseinate was detrimental to meat exudate gelation, resulting in lower final G′ (Pa) values than those observed for the control. © 1999 Society of Chemical Industry     

The rheological properties of exudates from cured porcine muscle: effects of added polysaccharides and whey protein/polysaccharide blends

Meat exudates collected from massaged cured porcine M semimembranosus were used to observe changes in gelation properties of test exudates containing added polysaccharides, both on their own and in combination with selected whey protein concentrates (WPCs). Three polysaccharide powders, namely sodium alginate, low‐methoxy (LM) pectin and modified potato starch, were assessed at a residual powder level of 2% with Na alginate used at a 0.5% level. Polysaccharides were evaluated both individually and as dry blends with selected WPCs. WPCs assessed included high‐gelling A 35%, B 75% and C 55% protein β‐lactoglobulin powders, as well as a regular 76.5% protein, WPC D. All WPCs were incorporated at a 2% residual powder level in the final meat. Treatment and control meat samples and resulting exudates were prepared in duplicate with analysis performed in triplicate. Viscoelastic properties of control and test meat exudate samples (n = 6) were analysed using control stress rheology in oscillatory mode. Exudates were heated from 20 to 80 °C at 1 °C min⁻¹ with subsequent cooling after 30 min to 20 °C at 1 °C min⁻¹. Combinations of high‐gelling WPCs (especially β‐lactoglobulin) together with modified starch or pectin were found to increase storage modulus G′ (Pa) values compared with control values, with significant (P < 0.05) synergies being observed on dry blending these ingredients. Sodium alginate was found to have a negative effect on G′ (Pa) results, giving lower values compared with control treatments. © 1999 Society of Chemical Industry     

我国沿海主要海域雌性三疣梭子蟹呈味成分含量的比较

以我国渤海、黄海、东海和南海4个海域中雌性三疣梭子蟹的肝胰腺、性腺和体肉为研究对象,采用电子舌、氨基酸自动分析法以及高效液相色谱法研究不同海域的生长环境对雌性三疣梭子蟹3个可食部位游离氨基酸含量和呈味核苷酸化合物的变化,并采用滋味强度值和味精当量对呈味成分的强度进行评价。结果表明:电子舌可对4个海域中雌性三疣梭子蟹的肝胰腺、性腺和体肉进行有效区分;在肝胰腺部分,游离氨基酸总量是3个可食部位最高的,3种呈味核苷酸中肌苷酸和腺苷酸的含量较高;在不同海域中,渤海肝胰腺组游离氨基酸总量最高,为3 315.05 mg/100 g,且其味精当量值最高,为15.87 g MSG/100 g;南海肝胰腺组游离氨基酸总量最低,但甜味氨基酸含量所占比例最高,为63.10%,并且呈味核苷酸含量最高,肌苷酸和腺苷酸的滋味强度值大于1。蟹的性腺部分,呈味核苷酸含量与味精当量值是3个可食部位中最高的,其中南海性腺的味精当量值为36.46 g MSG/100 g,是4个海域中最高。蟹的体肉部分中肌苷酸含量较高,黄海体肉肌苷酸组中含量较低,其滋味强度值小于1,对体肉的滋味无直接贡献,但黄海体肉组游离氨基酸总量最高,为2 564.44 mg/100 g;东海体肉组的味精当量值最高,为7.19 g MSG/100 g。     

Hot water bath treatments assisted by microwave energy to delay postharvest ripening and decay in strawberries (Fragaria × ananassa)

BACKGROUND: A lab‐scale approach using microwave (MW)‐assisted hot water treatments was developed and tested to assess the potential of this heating method to delay postharvest ripening and decay in strawberries. Strawberries (Fragaria × ananassa) immersed in water were exposed to microwaves at a frequency of 2450 MHz for 3 min at 514 W or 1 min 50 s at 763 W to reach an average temperature of 43.8 ± 0.6 °C at the fruit centre. Another batch was treated in hot water at 45 °C for 15 min, and a final batch was not treated (control). RESULTS: After 9 days of refrigerated storage (3 °C and 90% relative humidity), all heat‐treated strawberries showed significant retention of quality parameters such as colour and firmness and significantly lower yeast and mould populations (P < 0.05). CONCLUSION: Strawberries subjected to MW‐assisted hot water treatments showed significantly better retention of lightness compared with conventionally treated berries. A short (1 min 50 s) treatment at 763 W was the best choice to prevent strawberry decay. Copyright © 2011 Society of Chemical Industry