Comparison of the Cryoprotective Effects of Trehalose,Alginate, and Its Oligosaccharides on Peeled Shrimp (Litopenaeus Vannamei) During Frozen Storage

The cryoprotective effects of trehalose, alginate, and its oligosaccharides on peeled shrimp (Litopenaeus vannamei) during frozen storage was investigated by monitoring thawing loss, color, texture, myofibrillar protein content, Ca²⁺‐ATPase activity, and performing microscopic structural analysis. Data revealed significant (p < 0.05) inhibitory effects on thawing loss and textural variables (springiness and chewiness) in trehalose‐, alginate oligosaccharides‐, and sodium pyrophosphate‐treated shrimp compared with the control and alginate‐treated batches. L* values revealed that these saccharides had a positive effect on color stability during frozen storage. In addition, the results of chemical analyses showed that trehalose and alginate oligosaccharide treatments effectively maintained an increased myofibrillar protein content and Ca²⁺‐ATPase activity in frozen shrimp. In addition, hematoxylin & eosin staining and SDS‐PAGE confirmed that these cryoprotective saccharides slowed the degradation of muscle proteins and the damage to muscle tissue structures. Overall, the application of trehalose and alginate oligosaccharides to peeled frozen shrimp might maintain better quality and extend the commercialization of these refrigerated products.     

Ultrasound-assisted liquefaction of rosemary honey: Influence on rheology and crystal content

Crystallization of honey is a common process of the honey industry. Liquid honey is preferred by most of the consumers and by food companies for ease of handling. A better method compared to expensive and time-consuming heating is desirable to accelerate the liquefaction and retard the crystallization process in honey. In this work, samples of crystallized honey were liquefied by an ultrasonic bath of 40 kHz at temperatures of 40-60 °C for 20, 40 and 60 min. Then, the rheological properties and crystal content were analyzed and compared to only heat-treated samples. Results show that an ultrasound treatment speeds up the liquefaction of honey especially at temperatures below 50 °C. Lower temperatures preserve the honey’s quality and save the energy consumption. In addition, ultrasound-treated samples are clearer and more transparent than only heat-treated honey samples. The amount and size of the crystals were also smallest in the ultrasound treated samples.     

Cryoprotective Role of Exogenous Trehalose in Frozen Dough Products

Aim of this work is to study the cryoprotective role of extracellular trehalose in the production of bakery products from frozen dough. Therefore, different levels of trehalose (up to 200 ppm) were incorporated in dough/bread samples made from white and whole-wheat flour, and their quality (loaf volume, weight loss during baking, crust and crumb color) and texture characteristics (dough, crust and crumb firmness) were examined during frozen storage. To investigate the role of trehalose on dough behavior, the sugar content (glucose, fructose, and sucrose) of dough samples composed with or without trehalose was monitored, and dough microstructure was also analyzed with scanning electron microscopy. The cryoprotective effect of trehalose was confirmed, and it was found proportional to its level for both flour types. Trehalose can improve dough behavior under freezing conditions in terms of bread volume and texture characteristics.     

抗冻蛋白对冷冻虾夷扇贝闭壳肌持水性及质构特性的影响

为探究抗冻蛋白对冷冻虾夷扇贝闭壳肌持水性及质构特性的影响，以虾夷扇贝闭壳肌为原料，分别采用0.2 g/100 mL抗冻蛋白、3.0 g/100 mL焦磷酸钠和3.0 g/100 mL海藻糖溶液3 种抗冻剂进行真空浸渍，检测样品得率、离心损失、质构、色泽、水分分布及迁移状态、冰晶形态以及组织微观结构等指标。结果显示，抗冻蛋白组闭壳肌硬度、黏聚性及质子密度图像亮度与新鲜闭壳肌几乎一致，且显著高于焦磷酸钠和海藻糖组。而相比于其他浸渍组，抗冻蛋白组得率、弹性及剪切力显著增加，T21显著缩短（P＜0.05）。由光学显微镜和扫描电子显微镜观察可知，抗冻蛋白组的冰晶细小且呈球状，肌纤维结构较清晰完整，冰晶平均横截面积较空白组减少了65.06%。该研究证实，抗冻蛋白具有吸附于冰晶表面且抑制冰晶生长、修饰冰晶形态的作用，通过真空浸渍处理后，其对冷冻虾夷扇贝闭壳肌持水性及质构特性的调控作用优于焦磷酸钠、海藻糖，是一种有效的冻品品质调控手段。     

Sugar and Protein Profiles of Omani Honey from Muscat and Batinah Regions of Oman

Fifty-one samples of Omani honey were analyzed for their contents of glucose, fructose, maltose, and sucrose. The Fructose/glucose ratio and its role in honey crystallization were also studied, as well as the protein content of the honey samples. This study has shown that the mean percentage of reducing sugars lie within the limits set by local Omani legislation. Fructose and glucose represented the largest portion. Maltose and sucrose levels were low 3.62 kg/100 kg and 1.29 kg/100 kg, respectively. Most honey samples did not crystallize after 18 months of storage. Protein content in all samples was low with an average of 2 kg/100 kg. Fructose, glucose, and sucrose levels were higher in summer honey samples (69.7 kg/100 kg) than the winter ones (60.6 kg/100 kg).     

Crystallization of Honey at −20°C

Honeys from different regions of the province of Buenos Aires were stored at ?20°C, and factors that affect crystallization were analyzed. Crystals were observed by light microscopy. Firmness, adhesivity and viscosity of the samples were measured. Honey was characterized by determining the water activity, turbidity, moisture, fructose, and glucose contents. Results show that the viscous characteristics of the samples depend on the number, size, and disposition of crystals. Various honey samples exhibited Newtonian, pseudoplastic, and thixotropic behaviors. Crystallization was favored at higher moisture contents, suggesting that the parameters that affect honey crystallization at room temperature have a different effect at freezing temperatures. Honey that presented higher values of firmness had a moisture content lower than 17%, and a linear inverse relationship was observed between the adhesivity and firmness of honey samples.     

海藻糖、海藻胶及寡糖对蒸煮南美白对虾的抗冻保水作用

为探索海藻糖类在冷冻熟制水产品中的应用效果,以蒸煮南美白对虾为研究对象,以焦磷酸钠为阳性对照,研究海藻糖、海藻胶及寡糖对蒸煮虾仁的抗冻、保水作用。结果表明：－18 ℃冻藏6 周后,1.0 g/100 mL海藻糖、海藻胶寡糖浸泡处理,显著降低了冷冻蒸煮虾仁解冻和蒸煮损失率（P＜0.05）,其与焦磷酸钠保水效果无显著性差异（P＞0.05）。在整个冻藏期内,0.5、1.0 g/100 mL海藻糖和海藻胶寡糖处理,虾仁肌肉a*值保持效果显著优于其他处理组（P＜0.05）,表明该2 种糖类对蒸煮虾仁色泽具有较好的保护。随着冻藏时间延长,不同处理组虾仁水分含量、水分活度和质构特性均呈逐渐下降趋势,其中以海藻糖、海藻胶寡糖处理对虾仁水分、质构特性保持效果较好,且显著优于蒸馏水和焦磷酸钠组（P＜0.05）。经组织结构观察发现,1.0 g/100 mL海藻胶寡糖处理虾仁,肌纤维排列致密、无扭曲变形,且肌肉中无较大间隙或孔洞产生,表明海藻胶寡糖具有抑制肌肉间隙冰晶生长、保护肌肉组织完整性的作用。结果可为开发一种安全、高效、适用于冷冻蒸煮虾仁的无磷保水剂提供参考。     

黑芝麻复合蜜丸货架期预测及包装方式对其贮藏品质的影响

以黑芝麻复合蜜丸为研究对象,以酸价和过氧化值为评价指标,考察不同储藏温度对其品质的影响;在此基础上,通过构建Arrhenius模型对裸包装条件下的黑芝麻复合蜜丸的货架期进行预测。为进一步延长货架期,设置4种不同包装形式对黑芝麻复合蜜丸进行包装,同时考察不同包装方式对其水分、质构、理化特性等贮藏品质的影响。结果表明：与对照组相比,充氮、包壳、蜡封对阻止黑芝麻复合蜜丸水分下降、硬度和酸价上升均有一定的作用,其中以蜡纸+药丸壳+蜡封+锡箔纸+聚乙烯塑料袋这种包装形式效果最佳。该研究结果为蜜丸类产品的储存提供参考。     

SENSORY AND PHYSICAL CHARACTERISTICS AND STORAGE STABILITY OF HONEY-FLAVORED LOW-FAT EXTRUDED CHIPS

Consumer demand for low‐fat “healthy” snacks challenges manufacturers to improve the health profile of their products while maintaining their appetizing taste. The objectives of this study were to: (1) investigate the effect of addition levels of honey on texture and consumer acceptability of extruded, baked low‐fat/honey‐flavored chips; (2) determine the degree of liking for the product; (3) and evaluate the influence of honey on storage stability. The product, consisting of grade A light amber honey (0, 6, 12, and 18%) in a corn masa/flour blend, was extrusion formed into a ribbon through a slit die. The product was baked, dried, packaged, and stored in an ambient environment. Increased honey level significantly increased flavor liking, sweetness and honey flavor intensity for the fresh and 10 week storage samples, and positively influenced consumer overall acceptability.     

Influence of trehalose addition on antioxidant activity,colour and texture of orange jelly during storage

The aim of this study was to investigate influence of partial replacement of sucrose with trehalose on phenolics, antioxidant activity, colour and texture of orange jelly during 135 days of storage under the light at room temperature. After preparation, phenol content was 1185.6 and 1050.3 mg GAE kg^?1 in orange jelly and orange jelly with trehalose addition, respectively. Loss of phenols during 135 days of storage in orange jelly was 27.8% in comparison with 9.14% in orange jelly with trehalose addition. Browning index of samples with trehalose addition had lower values than orange jelly after their preparation as well as after storage. Evaluated textural parameters were gel strength, rapture strength, brittleness and adhesiveness. After preparation, both jellies had the same gel strength and adhesiveness. Orange jelly had higher rapture strength and higher value of brittleness than orange jelly with trehalose addition.     

冻藏温度对大黄鱼色泽、质构和抗氧化性的影响

本文重点研究-20、-40、-80℃冻藏温度对大黄鱼色泽、感官、质构和抗氧化性的影响,并对感官各指标评分与感官综合得分进行比较。结果表明,与新鲜大黄鱼冻藏第0d（对照组）相比,不同冻藏温度下第60d的色泽均发生显著变化（p<0.05）,-20℃色泽变化幅度最大。时间延长导致感官各指标评分和综合得分下降,口感变差,综合得分能整体反映出鱼肌肉的感官变化情况,硬度、胶着性、咀嚼性和回复性下降,弹性先上升后下降,-80℃感官综合评分和质构指标下降最缓慢。丙二醛含量（MDA）增加,总抗氧化能力（T-AOC值）、超氧化物歧化酶（SOD）活力和谷胱甘肽过氧化物酶（GSH-PX）活力明显下降,-80℃抗氧化性指标变化速率最慢。冻藏温度越低,大黄鱼色泽、感官、质构和抗氧化性指标变化越缓慢,为大黄鱼冷冻保存提供数据支持。      

Influence Of Trehalose Addition On Instrumental Textural Properties Of Strawberry Pastes

Objective of this study was investigation of influence of trehalose addition (3, 5 and 10%) on instrumental textural properties of evaporated and freeze-dried strawberry pastes. As a control, strawberry paste without addition of trehalose was used. Addition of trehalose had influence on both, hardness and stickiness of the samples, but it is very important to define the amount of trehalose in order to achieve desirable properties. With addition of trehalose hardness of both, evaporated and freeze-dried samples decreased, from 29.89 N to 14.72 N for evaporated samples and from 184.83 N to 44.95 N in freeze-dried samples. Also, from those results it could be seen that freeze-dried samples were much harder than evaporated ones, regardless of trehalose addition. While hardness of samples decreased with addition of trehalose, stickiness increased. Stickiness values were from 0.016 N to 0.0102 N for evaporated samples, and from 0.066 N to 0.018 N for freeze-dried samples. Since evaporated samples had lower values for stickiness they were stickier than freeze-dried ones.     

The Composition,Rheological and Thermal Properties of Tajonal (Viguiera Dentata) Mexican Honey

Samples of Tajonal honey (Viguiera dentata) from Yucatan, Mexico with different moisture contents were studied for their physicochemical, crystallization, rheological, and thermal characteristics. The presence of crystals changed the flow behavior from Newtonian to non-Newtonian. A characteristic glass transition temperature (Tg') was found for each sample, and it was observed to be dependent of the initial moisture content but independent of the storage period. The temperature and latent heat of fusion were not affected by the crystallization phenomenon, while both the moisture content and the glucose/water ratio were useful indexes for crystal growth in honey. Crystallization process can be controlled by harvesting the product with higher moisture contents without exceeding the limits established by international regulations.     

Retention of β-Carotene Encapsulated in a Trehalose-based Matrix as Affected by Water Content and Sugar Crystallization

ABSTRACT: Retention of β-carotene encapsulated in an amorphous trehalose-gelatin matrix and surface color changes were studied during storage of samples at several water activities. The fractional retention could be described by a first order reaction kinetics. The higher retention of β-carotene (about 80% in 6 mo) was obtained in the not crystallized samples, while for crystallized samples exposed to water activity 0.75 the loss was almost complete. Trehalose crystallization could not be delayed by the presence of MgCl₂ as occurs in the pure sugar systems. Surface color change was not a sensitive indication of carotene retention, which was mainly related to excess water over that needed to form the dihydrate crystals.     

不同预冷温度对鲈鱼冰藏期间质构和色差的影响

以鲜活鲈鱼为对象,将其置于不同水温(15、10、5℃)中暂养0.5 h后,在冰藏条件下贮藏,分别在第0、3、6、9、12、15、18、21 d对鲈鱼的质构特性和色差进行测定,综合评价不同预冷温度对鲈鱼冰藏期间质构和色差的影响。研究结果表明,冰藏过程中,不同预冷温度下鲈鱼的硬度均随贮藏时间的延长呈小幅度降低(p<0.05);而内聚性和弹性的变化趋势并不明显,未呈现显著的规律性变化,只在小范围内上下波动(p>0.05),各处理组组间差异不显著(p>0.05)。可见,不同预冷温度对鲈鱼冰藏过程中鱼肉的质构特性影响不大。在不同预冷温度下,对照组和预冷组的鲈鱼在冰藏期间的亮度值和红度值均随贮藏时间的延长呈下降的趋势,黄度值呈缓慢上升趋势,总色差出现不同程度的上升。15℃预冷处理能延缓鲈鱼冰藏时色泽变化,可以较好保持鱼肉的亮度值和红度值。     

Effect of Trehalose on the State of Water,Protein Denaturation and Gel-Forming Ability of Weever Surimi

The freshness and gel-forming ability of surimi decreased during frozen storage, while trehalose inhibits biological damage at low temperatures and stabilizing protein structures during freezing and freeze-drying. This study investigated the effect of trehalose at different concentrations (2.5–10 g/100 g wet materials) on the state of water, protein denaturation, and gel-forming ability of weever surimi during frozen storage at ?18°C for 90 days. The addition of trehalose increased the unfrozen water amount, regardless of level of addition differences, resulting decreased inactivation rate of calcium-adenylpyrophosphatase, and increased gel-breaking force and gel deformation of weever surimi throughout the frozen storage. Therefore, the addition of trehalose increased the gel-forming ability of weever surimi.     

Structural characteristics of crystals formed in palm oil using sorbitan tristearate and sucrose stearate

The formation and stabilization of fat crystals in palm oil (PO) by the templating effects of sorbitan tristearate (STS) and sucrose stearate (S-370) were examined. We observed that the crystallization mechanism occurred via heterogeneous nucleation, which was induced by co-crystallization or seeding, after the addition of STS or S-370, respectively. Overall, both emulsifiers, STS and S-370, caused an increase in the hardness of PO, which was related to changes in the microstructure. In addition, the intensity of this effect was shown to be dependent on the emulsifiers concentration. In differential scanning calorimetry analysis, S-370 proved to be associated predominantly to the crystallization of high-melting triacylglycerols (TAGs), while STS showed to actuate the crystallization of high and low-melting TAGs. Moreover, the addition of STS improved the polymorphic stability of the PO, while the use of S-370 resulted in a soft texture at lower temperatures.     

Effects of sunflower honey on the physicochemical,microbiological and sensory characteristics in set type yoghurt during refrigerated storage

The primary purpose of this research was to monitor the influence of sunflower honey addition (2%, 4% and 6% w/v) to yoghurt milk on survival of the microbial flora of yoghurt and the physicochemical and sensory characteristics during refrigerated storage for 4 weeks. The water activity decreased according to the addition of honey with higher concentrations in the storage period (4°C). At the end of fermentation, pH values of yoghurt samples ranged between 4.33 (without honey) and 4.52 (addition of honey with 6%). The highest water holding capacity, consistency and the lowest brightness values were determined in the groups produced with 6% honey addition. The water holding capacity and a* (redness) values of the honey incorporated yoghurt samples increased during storage. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus values of the yoghurt with honey increased compared with the control group samples (P < 0.01). Addition of honey to yoghurt milk has affected the vitality of the characteristics starters in the incubation and storage time of the yoghurt samples (P < 0.01). Optimum sweetness was obtained with the samples containing 4% honey level.     

蜂蜜干粉对肉肠品质影响的研究

为了提高肉肠类产品的感官品质及出品率,研究添加蜂蜜干粉对肉肠品质和出品率的影响。通过单因素试验研究了蜂蜜干粉添加量对肉肠贮藏期间色差、质构、低场核磁共振、蒸煮损失及感官评价等指标的影响。试验结果表明:在蜂蜜干粉添加量小于4.0%以内,随着蜂蜜干粉添加量的增加,肉肠品质变化显著,肉肠呈明亮、鲜红色,硬度和咀嚼性显著减小,弹性提高;同时低场核磁共振和蒸煮损失测定结果表明,产品的持水性也增强,出品率增高,蜂蜜干粉添加量为原料肉的3.5%左右较好。     

Effect of postharvest storage conditions on the colour and freshness parameters of raw honey

The influence of temperature (25, 30, 35 and 40 °C) and storage time (up to 62 or 104 days) on colour; hydroxymethyl furfural (HMF) content; and diastase index (ID) of citrus, rosemary, eucalyptus, polyfloral and honeydew honey was evaluated. Decreases in luminosity, whiteness index, hue and chroma with the increase in temperature and storage time were observed to different extents depending on the botanical origin of the honey. At all temperatures, the highest values of chromatic parameters throughout the whole period of storage corresponded to citrus honey. Honeydew honey showed the lowest values and the fewest colour differences. Principal component analysis explained 89% of the variations. PC1 (73%) separated honey types at lower temperatures in terms of colour parameters. PC2 (16%) described variations in HMF and ID in relation to storage conditions. Honey type had a much greater influence on HMF, ID and colour than storage conditions. The evaluated postharvest treatments did not alter the characteristic colour of each type of honey as long as the commercial requirements for freshness parameters were met.