Effect of furcellaran incorporation on gel properties of sardine surimi

Effects of furcellaran, powder (FURP) and solution (FURS), incorporation (2-8% based on surimi solid content) on gel properties of sardine (Sardinella albella) surimi were investigated. Breaking force, hardness, gumminess, chewiness, and whiteness of gels increased with increasing FURP or FURS contents (P < 0.05), where the highest values were observed in gel containing 8% FURS (P < 0.05). Expressible moisture content of gel decreased as levels of furcellaran increased (P < 0.05). The gel deformation, springiness, and cohesiveness were not affected by furcellaran (P > 0.05) as well as the polymerization of myosin heavy chain as visualised by SDS-PAGE. FURP and FURS could enhance the interconnection between chains during heating as indicated by the higher G′. Addition of furcellaran, especially FURS, up to 6% increased sensory property of resulting gel (P < 0.05). Anywise, an abatement in overall likeness score was found in gel with 8% FURS. Finer and denser microstructural network was observed in gel containing 6% FURS when compared to control. Therefore, furcellaran, prepared as solution, at an appropriate level can improve the overall quality of sardine surimi.     

不同干燥方法对大豆分离蛋白功能性质的影响

采用离心喷雾干燥、真空冷冻干燥、热风干燥、微波干燥对大豆分离蛋白进行干燥，研究干燥后的大豆分离蛋白的功能性质。结果表明：微波干燥的大豆分离蛋白粘度较大，而乳化性、吸水性、吸油性和水合能力小；热风干燥和喷雾干燥的大豆分离蛋白功能性质相似；真空冷冻干燥对大豆分离蛋白功能性质影响小。     

Physicochemical and functional properties of lentil protein isolates prepared by different drying methods

Lentil protein isolate (LPI) extract was converted into powder by freeze drying, spray drying and vacuum drying. Differences in particle size distribution, protein subunit composition and colour and surface morphology were observed amongst the three drying methods. Spray and freeze-dried LPI powders exhibited higher solubility (81% and 78%, respectively) compared to vacuum dried powders (50%). The spray dried powders showed a low water absorption capacity (0.43 ± 0.02 g/g) compared to freeze (0.48 ± 0.02 g/g) and vacuum-dried (0.47 ± 0.01 g/g) LPI powders. Spray and freeze-dried powders displayed better gelation ability and higher gel strength, compared to vacuum-dried powder. Both spray and freeze-dried gels showed typical viscoelastic gel characteristics, with G′ dominating over G″ and very low loss tangent. The holding time required for gelation of vacuum dried powder at 90 °C was significantly longer, compared to spray and freeze dried powders. Hence, drying methods used for preparation of lentil protein isolate powders can affect physicochemical and associated functional properties.     

Effects of air-impingement jet drying on drying kinetics and quality retention of tomato slices

Food Science and Biotechnology - The purpose was to explore the drying kinetics, the moisture effective diffusivities, color, total polyphenols, lycopene and antioxidant activities of dried tomato...     

Effects of conventional and multistage drying processing on non-enzymatic browning in tomato

The effect of different drying temperatures on the development of non-enzymatic browning in tomato was studied. In particular, the influence of product moisture and temperature on the colour change during drying at various temperatures in the range of 50–90 °С was investigated. The extent of browning was evaluated spectrophotometrically as tomato extracts absorbance at 420 nm. As a result of analysis of experimental data, a multistage drying process of tomato was developed. In this method, drying was realized at decreasing air temperature, arranged such, that the temperature inside the fruit did not exceed acceptable level of 55 °С. Higher product quality and shorter drying time in comparison with the conventional drying at constant air conditions were observed.     

不同干燥方式对黑茶品质的影响

目的 黑茶传统自然干燥工艺受天气、卫生、效率等因素局限,本文探讨黑茶采用现代机械干燥替代传统干燥的可行性。方法 以云南晒青毛茶渥堆叶为原料,采用不同干燥工艺(热风烘干、远红外干燥、炒干、微波干燥、光波干燥、微波光波混合干燥、晒干、晾干)制成黑茶。分析其感官品质、主要品质成分变化。结果 不同干燥方式加工的黑茶干茶色泽、汤色、叶底基本一致,香气和滋味相差较大。其中热风烘干的黑茶陈香突出,综合品质最高,其游离氨基酸含量较高。远红外干燥的黑茶滋味略带苦味,陈香较弱,其咖啡碱、儿茶素总量较低,滋味的浓度、协调度均不足。炒干的黑茶条索更紧结,香气带陈香较清新,滋味醇和,其可溶性糖、含量相对较高。微波干燥的黑茶滋味甜醇,稍带闷气,其可溶性糖、茶红素含量较高。光波干燥的黑茶茶滋味有甜醇风味及特殊香气,其游离氨基酸含量相对较高。微光波混合干燥的茶有甜醇味,香气略陈,其游离氨基酸、可溶性糖和咖啡碱的含量均介于微波与光波干燥之间,茶多酚的含量高于其他干燥方式。晒干的茶滋味涩,香气为日晒气,其游离氨基酸、可溶性糖含量较低,茶褐素含量高,儿茶素含量较高。晾干的茶滋味有涩味,口感低淡,其游离氨基酸、可溶性糖含量较低,茶褐素含量相对较高。 结论 结合感官品质和理化分析,黑茶加工干燥环节,热风烘干、炒干、微波干燥、光波干燥、微光波混合干燥等现代机械干燥方式可以取代传统的晒干和晾干方式。     

Effects of microwave and infrared drying on the quality of carrot and garlic

The effects of microwave and infrared drying on the quality of carrot and garlic were studied and compared with the effects of conventional hot air (tray drier for carrot and fluid bed drier for garlic) drying. The quality of carrot and garlic were evaluated by instrumental and sensory analysis. Rehydration, moisture content, water activity, particle density, bulk density, porosity and colour values were obtained for microwave, infrared and hot-air dried vegetables. In addition, total moisture content versus time was represented by drying rate curves of carrot and garlic samples. Finally, free moisture content versus drying rate were compared for the three different drying methods.     

干制状态气体对胡萝卜干燥过程特性及制品品质的影响

分别以空气及氮气、二氧化碳气体置换部分空气等3种状态的气体作为干燥介质，采用QTM干制实验设备对胡萝卜粒进行对比干燥试验，探讨干制状态气体对胡萝卜粒的干燥过程特性及制品品质的影响。结果表明，干制状态气体与胡萝卜粒的干燥过程特性及制品的品质关系密切。降低干燥室内气氛了体的氧气含量，可维持较佳的糖酸比及显著提高Vc保存率，制品的质量较好；在气体的氧气含量相同状态下，充人氮气置换部分空气的制品质量最好，且具有较高的干燥速度和复水比。     

Effects of drying on the phenolics content and antioxidant activity of muscadine pomace

Three drying technologies [i.e., vacuum belt drying (VBD), hot air drying (HAD), and freeze drying (FD)] were evaluated for the processing of muscadine pomace in terms of their impact on drying time requirement, moisture content (MC), water activity (a_w), total phenolics content (TPC), and antioxidant activity (AA). Muscadine pomace discs of two thicknesses (2 and 4 mm) were dried using 16 different time-temperature combinations for VBD, 12 different time-temperature and air velocity combinations for HAD, and one treatment for FD. The TPC and AA in lyophilised samples were 583 ± 8 and 608 ± 16 μmol GAE/g d.w. and 2.21 ± 0.15 and 2.30 ± 0.17 mmol Fe²⁺ E/g d.w. for the 2 and 4 mm thick discs, respectively. The VBD treatment of 60-80-100-100 °C for 60 min (i.e., TV2) for 2 mm thick discs showed the highest TPC value, and no significant (P > 0.05) differences were observed in AA of 2 mm thick discs dried by VDB and FD. The TPC and AA for the VBD treatment of 60-80-100-100 °C for 90 min and HAD treatment of 70 °C at 0.6 m/s for 3 h for the 2 mm thick discs were not significantly (P > 0.05) different compared to freeze dried samples. For 4 mm thick samples, the TPC and AA for the VBD treatments of 60-80-100-100 °C, 60-90-120-120 °C, 70-90-110-110 °C, 80-90-100-100 °C, and 90-105-120-120 °C for 90 min as well as 70-90-110-110 °C for 60 min were not significantly (P > 0.05) different compared to those for freeze dried discs. VBD is a promising drying technology, as the resultant products possessed high TPCs and were dried in less than ¼ of the time compared with that of FD.     

Effects of drying conditions in hybrid dryer on the GABA rice properties

In this study, pre-germinated rough rice was dried under various conditions using a hybrid dryer that incorporated heat pump dryer with fluidized bed drying (FBD) system in order to compare with the single-stage drying by hot air dryer. The main objective was to investigate the effect of drying conditions on the cooking and physical properties, nutrients and sensorial qualities of GABA rice products. It appeared that the FBD at 100–140 °C led to noticeable increase of head rice yield. The germination process caused the decline of gelatinization enthalpy of brown rice flour, the change of pasting properties, the reduction of cooking time and escalation of the total phenolic content, antioxidant activity and GABA content. The FBD at higher temperature significantly raised the degree of starch gelatinization and caused longer cooking time, higher hardness and adhesiveness of cooked GABA rice. Three-stage drying comprising FBD at 60 °C for 10 min in the first stage followed by FBD at 100 °C in the second stage and then heat pump drying at 45 °C together with tempering step between drying stages was recommended due to its superior GABA rice product quality.     

Effects of maturity and drying method on the physico-chemical and reconstitution properties of plantain flour

Effects of maturity and drying method on physical, physico-chemical and reconstitution properties of plantain flour were investigated. Colour ( L*a*b* ) parameters of dried flours were measured, and the delta chroma (Δ C ) and colour difference (Δ E ) were calculated. Particle size, physico-chemical (pasting) using Rapid Visco-Analyser and reconstitution properties of dried plantain flour were determined. Colour parameters of foam-mat [ L* (57.56–66.33), a* (5.29–6.77), b* (11.82–13.33)], sun [ L* (60.18–67.45), a* (5.43–5.88), b* (13.19–13.25)] and oven [ L* (58.78–66.44), a* (6.08–6.33), b* (11.96–12.78)] dried flours were significantly different ( P  < 0.05). Generally, more than 40% of the flours were retained by the 710 μm sieve. Generally, peak (–2.08–166.00), breakdown (1.25–29.42), final (–1.00–298.67) and setback (1.50–156.92) viscosities varied with drying method and maturity. Peak time and pasting temperature varied from 5.20–6.87 s and 92.30–94.55 ^°C, respectively. pH (4.26–4.97), titratable acidity (0.10–0.50% citric acid), soluble solids (3.25–30.76), moisture (8.77–65.99%) and dry matter (34.01–91.23%) contents were significantly ( P  < 0.05) affected by maturity and drying method.     

Effect of microwave vacuum drying and hot air drying on the physicochemical properties of durian flour

Unripe durian cv. Monthong was subjected to microwave vacuum drying (MVD) at 1200, 1600 and 2200 W and hot air drying (HAD) at 40, 50 and 60 °C to produce durian flour. Drying rate of MVD and HAD was 0.34–0.58 kg water kg dry solid^?1 min^?1 and 0.02–0.06 kg water kg dry solid^?1 min^?1, respectively. An increase in drying rate by either increasing hot air temperature or increasing microwave power decreased the degree of crystallinity from 21.95% to 2.31% and from 7.72% to 4.05%, respectively. Moreover, the increased drying rate caused a decrease in endothermic enthalpy (ΔH_gel) and pasting properties. Starch content of the durian flour was 41.40–47.03%. The starch granule morphology of durian flour was disrupted which indicated gelatinisation of flour during drying. Due to a short drying process, the MVD flour had less a*‐value (P ≤ 0.05) than the HAD flour.     

Effects of conventional and nonconventional drying on the stability of Bifidobacterium animalis subsp. lactis INL1

Freeze, spray, vacuum, microwave vacuum‐ and microwave freeze‐drying were applied to Bifidobacterium animalis subsp. lactis INL1. Freeze and microwave freeze‐drying showed the highest survival after drying. When a storage test (25 °C; oxygen) was performed, these cultures were the most sensitive ones at a_w = 0.23, but the addition of lactose improved their stability after 8 weeks. Flow cytometry was useful to assess viability after drying but not during storage. Our results show that dehydration technologies other than freeze‐drying might be suitable alternatives that deserve further investigation for the preservation of sensitive probiotic bacteria. Microwave drying rendered cultures of comparable characteristics to their conventional counterparts, requiring significantly shorter drying times.     

Effects of oxidative modification on gel properties of isolated porcine myofibrillar protein by peroxyl radicals

AAPH-derived (2,2′-azobis (2-amidinopropane) dihydrochloride) peroxyl radicals were selected as representative free radicals of lipid peroxidation to investigate the effects of oxidative modifications on isolated porcine myofibrillar protein structures as well as their rheological and gelling properties. Incubation of myofibrillar protein with increasing concentrations of AAPH resulted in a gradual increase (p < 0.05) in carbonyl content and SH → S–S conversion. Results from SDS-PAGE indicated that medium (~ 1 mM) and relatively high (> 3 mM) concentrations of AAPH induced aggregation of myosin and denaturation of myosin, troponin and tropomyosin, respectively. These structural changes resulted in changes on gelation of myofibrillar protein. Low level protein oxidation (AAPH ≤ 0.5 mM) had no remarkable effect (p > 0.05) on the viscoelastic pattern of myofibrillar protein gelation. Moderate oxidative modification (AAPH ~ 1 mM) enhanced the water-holding capacity (WHC) and texture properties of gels, while further oxidation (AAPH > 3 mM) significantly reduced the gel quality.     

Study of the drying behaviour in peeled and unpeeled whole figs

Aim of this study was to estimate the effect of peeling on drying kinetics and effective diffusivity D_eff of figs (Ficus carica L. var. tsapela) during air-drying. For this purpose three temperatures (45, 55 and 65 °C) were tested. The Logarithmic model was chosen to describe the drying curves among seven drying models. The estimated drying constants were associated with the drying temperature by an Arrhenius type equation. The ratio of peeled to unpeeled relaxation times was found to be 0.54 ± 0.16. The D_eff of figs (peeled and unpeeled) was estimated by the method of slopes. The D_eff of the peeled figs was higher than this of the unpeeled figs presenting smaller differences as drying temperature was increased. This behaviour was attributed to the case hardening effect which is faster developed as the drying rate increases during high temperature drying.     

小径原条剥皮方式对木材干燥的影响

本文对具有四种剥皮状态的次生林白桦小径木的干燥特性进行了比较研究，分析了干燥时间、干燥速度、干燥质量、干缩率和干燥过程中的分层含水率等。初步探讨了平行条状剥皮原条干燥的合理性，并指出干燥温度对原条干燥质量的影响较大。     

Drying rate control in the middle stage of microwave drying

Microwave drying of apples at constant temperatures follows typical drying curves. The middle stage of the drying process shows a faster drying rate and accelerated moisture evaporation. Meanwhile, more flavors are lost, surface color is degraded, and charring often occurs in this stage. To improve the drying effects, drying curves were controlled and changed in this study. The drying curve was linearized by automatically varying drying temperatures in the middle stages. The controlled drying process therefore led to an optimized temperature profile. To simplify the drying methods, apples were further dried with the obtained temperature profile, while drying curves were online monitored but not controlled. It was proved that slowing down the drying rate in the middle stage could improve the product quality in terms of color, flavor, and overall appearance, while the drying time and energy consumption were still acceptable (within 200 min and 22 kJ/g, respectively).     

Studies on the effects of microwave drying and cabinet tray drying on the chemical composition of volatile oils of garlic powders

Garlic cloves in the form of bits were dried in a cabinet tray dryer and a microwave dryer, and pulverized to obtain free flowing powder. The volatile oil was obtained by hydro-steam distillation method. Fresh cloves and the powders resulting from the two drying methods were used for obtaining the volatile oil, which was analyzed by GC-MS. The studies were mainly restricted to comparing the effect of drying methods on the volatile oil composition of the powders. Although the drying time was reduced considerably from 8 h in a cabinet dryer to 0.25 h in a microwave dryer, essential oil yield and color values were lower, and flavor quality varied considerably. The relative concentrations of major peaks such as diallyl disulfide, diallyl tetrasulfide increased in both the drying methods, and it was more so in microwave-dried samples. However, the concentrations of the other two major peaks, diallyl trisulfide and allyl methyl trisulfide, decreased in both drying methods, and they were lower in microwave-dried samples. Hunter values of L and b were lower for samples obtained by microwave drying as compared to those of cabinet-dried samples.     

Effects of different drying treatments on the stability of carotenoids in Taiwanese mango (Mangifera indica L.)

The stability of carotenoids in Taiwanese mango as affected by different drying treatments was studied. Mangoes were soaked in 1% sodium hydrogen sulfite solution or 1% ascorbic acid solution, prior to hot-air drying and freeze-drying. Results showed that in most cases, the highest yield of the epoxy-containing carotenoids was achieved by freeze-drying plus soaking in 1% sodium hydrogen sulfite solution. However, freeze-drying plus soaking in 1% ascorbic acid solution resulted in the highest retention of all-trans-β-carotene and its cis isomers, all-trans-zeaxanthin and its cis isomers, as well as cis-lutein. Nevertheless, for hot-air drying, with or without soaking, a mango product of deep orange colour was produced. On freeze-drying, mango could generate yellow colour, while a lighter color was observed when soaked in antioxidants.     

Characterisation of osmotically dehydrated papaya with further hot air drying and microwave vacuum drying

Papaya was subjected to osmotic dehydration (OD) prior to hot air drying (HA; 70 °C) and microwave vacuum drying (MVD; 3.75 W g^?1 and 13.3 kPa). An increase in immersion time in a sucrose solution [65/100 g (w/w)] at 40 ± 2 °C from 0 to 4 h decreased moisture content from 7.5802 to 1.2215 kg water kg dry solid^?1. During HA and MVD, effective moisture diffusivity was in the range 7.09 × 10^?8 to 9.13 × 10^?8 m² s^?1 and 2.85 × 10^?6 to 3.50 × 10^?6 m² s^?1, respectively, depending on immersion time. The hue angle of HA samples was 0.83–0.91, whereas that of MVD samples was 48.55–50.32. Both drying methods decreased springiness. Porosity was clearly observed in MVD samples. Rehydration rate was enhanced by increased immersion time and MVD (P ≤ 0.05). From preference mapping, MVD samples were more preferable than HA samples. Moreover, MVD samples with 1–3 h OD were more preferable than those with 4 h OD.