Effect of Fruit Properties on Pomegranate Bruising

Pomegranate fruit quality is adversely affected by bruise damage. Bruises are formed by a variety of static loads and dynamic impacts on the fruit when it strikes any other object during handling, sorting, packaging, or transportation. In order to be able to reduce this damage, it is necessary to ascertain the influence of fruit properties on bruise susceptibility. An experimental study was performed with varying storage time, temperature, and impact region. In these experiments, pomegranates were dropped from three heights onto a flat aluminum surface. Significant effects on bruising in relation to storage time, temperature, impact region, and their interactions were found (p < 0.05). It was concluded that higher fruit temperature, firmness, and peel thickness reduced bruise damage to the pomegranate fruit. Moreover, storage time and increased radius of curvature increased the bruise volume and bruise area, respectively.     

冷冻处理对果蔬的影响及其应用

讨论了冷冻处理对果蔬中蛋白质、糖分、维生素等营养成分以及颜色、风味、微观结构等方面的影响，阐述了其在果蔬产业中，尤其是热敏类成分含量较高果品的榨汁、浓缩等工艺中的应用现状及前景，强调了冷冻处理在果蔬产业中的应用依然存在很大的挖掘空间。     

Factors affecting resistance of banana fruit to compression and impact bruising

Factors affecting resistance of banana fruit to bruising were investigated by estimating the minimum (threshold) compression forces and impact energies (both applied through 8 mm dia balls) required to produce bruises on fruit. In a survey of fruit from 11 sites in St Lucia at altitudes from 4 to 290 m, high thresholds for compression bruising were associated with fruit releasing large amounts of latex at harvest, an indicator of their high turgidity. In experimental work, fruit harvested in early morning (07.45), when their turgidity would have been highest, required 5–49 N compression to cause bruises compared with 4–55 N for later harvested fruit (at both 10.45 and 13.45). Water loss induced by leaving fruit 1 and 2 days at ambient conditions between harvest and application of bruising treatments led to reductions in thresholds for compression bruising from 5–35 to 4–32 and 4–29 N, respectively. The importance of water loss in this effect was confirmed in an experiment in which the initial rate of decline in thresholds for compression bruising was reduced by keeping fruit at high relative humidity. Fruit at 30^°C had a lower compression bruising threshold (3–31 N) than those at 13–5, 19 and 24–5^°C (4–52, 4–72 and 4–46 N, respectively). In contrast, impact bruising thresholds were affected by delay after harvest and temperature in the opposite direction to compression bruising thresholds, increasing from 93 to 120 μJ following a 2-day delay after harvest and from 74 to 104 uJ as a result of elevating temperature from 19 to 30^°C. Further work will therefore be necessary to determine which of the two types of influence is most prevalent in the postharvest handling chain before recommendations on modified handling procedures can be made.     

The effect of storage pressure on the mechanical properties of paddy grains

To investigate the effect of storage pressure and storage time on the mechanical properties of paddy grains, an experimental study was carried out to determine the mechanical properties of paddy grains compressed at minor axis orientation using the Texture Analyzer. The paddy grains were stored under different pressures and for different time. The results showed that as the storage pressure increased from 0 to 300 kPa, the rupture force of paddy grains stored for 60 days decreased from 81.58 to 73.78 N, the rupture energy from 8.10 to 6.27 mJ, the rupture strain from 0.1392 to 0.1168, the apparent contact modulus of elasticity from 171.32 to 57.68 MPa and the maximum contact stress from 40.84 to 19.11 MPa. All of the mechanical properties of the paddy grains exhibited a linear relationship with storage pressure. As for the paddy grains stored under the pressures of 77, 100, 139, 200 kPa, as the storage time increased from 0 to 60 days, the rupture force of the paddy grains decreased from 81.58 to 79.58 N, 81.58 to 79.12 N, 81.58 to 78.21 N and 81.58 to 76.96 N; the rupture energy decreased from 8.10 to 7.55 mJ, 8.10 to 7.35 mJ, 8.10 to 7.08 mJ and 8.10 to 6.85 mJ; the rupture strain decreased from 0.1392 to 0.1309, 0.1392 to 0.1283, 0.1392 to 0.1257 and 0.1392 to 0.1213. The apparent contact modulus of elasticity decreased from 171.32 to 135.97 MPa, 171.32 to 121.77 MPa, 171.32 to 110.59 MPa and 171.32 to 83.32 MPa; the maximum contact stress decreased from 41.16 to 35.00 MPa, 41.16 to 32.45 MPa, 41.16 to 30.32 MPa and 41.16 to 14.97 MPa, respectively. The results revealed that both storage pressure and storage time have a significant effect on the mechanical properties of paddy grains.     

Determination of the fruit content of apricot and strawberry jams and spreads and apricot and peach fruit preparations by gravimetric quantification of hemicellulose

An innovative method developed for fruit content determination based on the quantification of hemicellulose was applied to apricot and peach fruit preparations, apricot and strawberry jams and spreads. For this purpose, the hemicellulose fraction was isolated from the alcohol-insoluble residue from peaches, apricots, and strawberries, yielding the amount of the respective fresh fruit per gram hemicellulose. Fruit preparations from peaches with 34.4%, 47.2% and 66.4% fruit content were produced using pectin and carrageenan, xanthan or starch, respectively, as hydrocolloids. Jams from apricots and strawberries were prepared with pectin. Fruit contents of apricot jams were 34.1% and 48.2%, and 36.6% and 46.4% in strawberry jams, respectively. Furthermore, a range of commercial apricot spreads and jams and one strawberry spread as well as apricot and peach fruit preparations were examined. The fruit content was calculated based on the amount of hemicellulose. Calculated fruit contents were in good agreement with the respective product specifications (e.g. 62.6% vs. 66.4%, 35.2% vs. 34.1%, 67.5% vs. 70.0% and 54.0% vs. 53.7%, respectively) with deviations ranging between 0.3% and 4.2%. Maximal deviation was found only in the case of a self-made peach fruit preparation (40.9% vs. 34.4%), where interference of added hydrocolloids and fruit ingredients probably resulted in significant overestimation of the fruit content. Although sample preparation needed to be adapted to different fruit matrices, this novel method proved to be suitable for the determination of fruit contents of fruit preparations, spreads and jams. For the first time, this method was successfully applied to industrially manufactured fruit products without knowledge of fruit specification and the complex recipes of jams, spreads, and fruit preparations, respectively.     

The effects of varying sugar content and fruit concentration on the physical properties of vanilla and fruit ice-cream-type frozen yogurts

In this study, the physical properties of samples of ice cream produced from yogurt with varying levels of sugar (18, 20 or 22%) and fruit (strawberry) concentration (15, 20 or 25%) were investigated. The results of the physical analysis indicate that as the amount of sugar and fruit increases, there is an increase in the first dripping time period, viscosity values and the overrun. However, complete melting times decreased in parallel with the increase in sugar content and fruit concentration. It was observed that an increase in the amount of sugar in vanilla frozen yogurt softened the structure. In strawberry ice-cream-type frozen yogurt, the structure hardened in parallel with the increase in fruit concentration. In addition, the results show that frozen yogurts with high sugar (V3) and fruit (St3) concentrations are the type most preferred by the panellists. The results of the sensory analysis suggest that frozen yogurt can be an alternative to other dairy products such as yogurt and ice cream.     

Savinase蛋白酶处理对粗纺毛织物性能的影响

粗纺毛织物以其质地丰厚、保暖性好深受消费者的喜爱,而毛织物在穿洗过程中易产生尺寸不稳定和毡缩现象,严重影响了织物的外观和服用性。针对以上情况,文章对粗纺毛织物的羊毛鳞片剥落的情况以及对织物性能的影响作了进一步的研究。首先采用双氧水进行预处理,然后采用Savinase蛋白酶对粗纺毛织物进行防缩整理,再对其进行强度、抗毡缩性、耐皱性、白度等性能测试,研究经Savinase蛋白酶处理后对粗纺毛织物性能的影响。通过测试发现,毛织物的防毡缩性能增加,断裂强力下降,织物白度增大,经纬向回复性都有所提高,织物变得较柔软,厚度减小,抗起毛起球性增加。     

Measurement of impact pressure and bruising of apple fruit using pressure-sensitive film technique

Impact pressure and bruising of apple fruit were measured by means of a pressure-sensitive film technique, in order to develop methods for assessing and predicting bruising of apples resulting from impact loads during the course of transport and handling. Results of impact tests with apples indicate that when the fruits are dropped from different heights onto different impacting surfaces, the bruise area and volume could be assessed and predicted by regression models based on the impact force obtained from the pressure-sensitive film (F_PSF). The coefficients of determination (R²) for bruise area and bruise volume were found to be 0.91 and 0.95, respectively.     

The effect of moisture content on the physico-mechanical properties of some hazelnut varieties

To better understand storage design requirements for hazelnuts, this research determined the physico-mechanical parameters (bulk density, true density, angle of internal friction, static coefficient of friction and dynamic coefficient of friction) of hazelnut varieties Tombul, Badem, Mincane, Çak?ldak and Sivri, for different structural surfaces. Physico-mechanical parameters (bulk density, true density, angle of internal friction, static coefficient of friction and dynamic coefficient of friction) were considered as the dependent variables, and moisture content (8%, 12%, 16%, 20%) as the independent variable. The temperature recorded in the laboratory during the experiments was 24.3 °C. The highest average value for bulk density (520 kg m⁻³) was recorded for the Sivri variety, the highest average value for angle of internal friction (35.4°) for the Badem variety, and the highest average value for true density (870 kg m⁻³) for the Mincane variety. The highest average values for static coefficient of friction (0.411) and the dynamic coefficient of friction (0.287) were recorded for concrete surfaces and the Badem variety.     

An investigation on the effect of pigments on the texture ability and mechanical properties of polypropylene BCF yarns

Abstract

In this work, the effect of five pigments on the mechanical and texturing properties of polypropylene BCF yarns has been investigated. The results showed that depending on the type, pigments may have a significant decreasing or increasing effect on the mechanical properties of polypropylene BCF yarns, although some of these differences may not be practically significant. As far as the bulk properties of the BCF yarns are concerned, a trend could not be established for the effect of pigments on crimp contraction and crimp modulus, but increasing the amount of pigments decreased the crimp stability of all BCF yarns. XRD and DSC analyses showed that the addition of pigments decreased the crystallinity index of the yarns depending on the type of pigment. DSC analysis showed a higher onset melting point after adding pigments with the exception of white one. FTIR spectra show no considerable reaction or interaction between polypropylene and the pigments employed in the masterbatch.     

Miniaturization of cellulose fibers and effect of addition on the mechanical and barrier properties of hydroxypropyl methylcellulose films

Cellulose fibers were miniaturized by microfluidics technology to decrease their size and incorporated in hydroxypropyl methylcellulose (HPMC) films to study the effect of addition of such fibers on the mechanical and barrier properties of HPMC films suitable for application in food packaging. The particle size of fibers and the mechanical properties, water vapor and oxygen permeabilities, total pore volume, and light and electron microscopy micrographs of films were analyzed. Incorporation of cellulose fibers in the films improved their mechanical and barrier properties significantly. This study is the first to investigate the use of microfluidics technology for the purpose of decreasing the size of cellulose fibers and the addition of reduced size microfibers to improve physical properties of HPMC films.     

Freezing protocol effect on quality properties of fruit tissue according to the fruit, the variety and the stage of maturity

Among the changes induced by freezing of fruits, it is still difficult to determine the major properties which are the most representative of quality variation. A range of characteristics (texture, color, soluble solids, water activity, water content, pH, titrable acidity) were determined before and after three different freezing protocols (at −20 °C in a cold chamber, at −80 °C in gas nitrogen convection chamber and after immersion in liquid nitrogen at −196 °C) for two fruit types (apple-Malus domestica Borkh- and mango - Mangifera indica L. cv. ‘KENT’-), two varieties of apples (Golden Delicious and Granny Smith) and two maturities of one variety (ripe and unripe Granny Smith). Freezing induced significant changes mostly in texture, color and soluble solids. Property variations due to freezing depended mainly on the type of fruit, to a lesser extent on the variety of apples studied and slightly on the maturity of Granny Smith apples. Among the freezing conditions tested, gas nitrogen convection at −80 °C appeared to be the best choice for limiting fruit quality degradation.     

Influence of fibre addition on the rheological properties of peach juice

The addition of dietary fibres is a tendency in several foods. Understanding the changes in food sensory and physical properties due to fibre addition is thus, essential for food process design. The present work has evaluated the influence of peach fibre addition on the rheological properties of peach juice. Flow behaviour and influence of fibre concentration on Herschel‐Bulkley model’s parameters were evaluated. The flow behaviour of the products was changed due to fibre addition, from Newtonian to pseudoplastic and then, Herschel‐Bulkley behaviour. The parameters could be well modelled by exponential (σ₀), power law (k) and sigmoidal (n) functions (R² > 0.98). The viscoelastic properties were evaluated for the most concentrated products. Variation of storage and loss modulus with the oscillatory frequency were well described by a power function (R² > 0.96), and dependency of its parameters with temperature was well modelled by Arrhenius’ model (k′, k″, R² > 0.94) and quadratic function (n′, n″, R² > 0.90).     

Effect of chopped/continuous fiber,coupling agent and fiber ratio on the mechanical properties of injection-molded jute/polypropylene composites

This paper presents the development of jute/polypropylene (PP) composites by twin-screw extrusion and injection molding. Jute/PP was compounded using twin-screw extruder and injection molded. The effects of chopped/continuous fibers, coupling agent and fiber ratio on mechanical properties were investigated. Tensile and flexural moduli of continuous jute/PP were greater than those of chopped fiber/PP. Tensile, flexural and impact strengths were greater in chopped fiber/PP along with elongation at break. Coupling agent improved the tensile and flexural strengths, and these increased with fiber content, whereas impact strength and elongation at break decreased with fiber loading. The results were analyzed using ANOVA and regression analyses.     

Impact of high intensity pulsed electric field on antioxidant properties and quality parameters of a fruit juice-soymilk beverage in chilled storage

The effects of high-intensity pulsed electric fields (HIPEF) treatment (35 kV/cm, 4 μs bipolar pulses at 200 Hz for 800 or 1400 μs) on the microbial stability, quality parameters and antioxidant properties of a fruit juice-soymilk (FJ-SM) beverage along the storage time at 4 °C were compared to those obtained by thermal pasteurization (90 °C, 60 s). HIPEF processing for 800 μs ensured the microbial stability of the beverage during 31 days; however, longer microbial shelf-life (56 days) was achieved by increasing the treatment time to 1400 μs or by applying a thermal treatment. Peroxidase and lipoxygenase of HIPEF treated beverages were inactivated by 17.5-29% and 34-39%, respectively; whereas thermal treatment achieved 100% and 51%. During the storage, vitamin C content and antioxidant capacity depleted with time, and they were higher in FJ-SM beverages processed by HIPEF than in those thermally treated. Instead, total phenolic content of beverages did not present significant changes over the time, and it was higher in the 1400 μs-HIPEF treated beverages. In general, color, soluble solids, pH, and acidity values were not significantly affected by the processing treatments. Beverage viscosity increased over time, regardless of the treatment applied. Hence, application of HIPEF may be a good alternative treatment to thermal processing in order to ensure microbiological stability, high nutritional values and fresh-like characteristics of FJ-SM beverages.     

The effect of fruit properties on the apricot bruises susceptibility

Some forces and impacts that occur during transporting and handling can reduce the apricot quality. Bruise damage is a major cause of fruit quality loss. Bruises occur under dynamic and static loading when stress induced in the fruit exceeds the failure stress of the fruit tissue. In this paper, two models were presented to evaluate the bruises susceptibility of apricots due to impact energy and peak contact force. Statistical prediction models of absorption energy were constructed to calculate “Ziaolmolki” apricot bruise susceptibility regarding fruit properties. The impacts were controlled by a pendulum. The regression models were made based on impact force and impact energy as the main independent variables and other parameters including fruit temperature, acoustic stiffness, colour parameter b* and radius of curvature. Pendulum was used to perform three levels of impact on apricot fruit. The main and interactions effects between variables were significant at 5 % probability level. It was demonstrated that increasing the temperature and curvature radius and lowering acoustical stiffness will reduce the bruise damage of the apricot fruit. Also, variance analysis indicated that three controlling factors, temperature, colour and impact force, significantly affected (P < 0.05) absorption energy.     

Comparison of the effect of sugars on the viscoelastic properties of sweet potato starch pastes

Viscoelastic properties of sweet potato starch (SPS) pastes (5% w/w) were studied in the presence of various sugars (sucrose, glucose, fructose, and xylose) at different concentrations (0, 10 and 20%) by small‐deformation oscillatory measurements. Dynamic frequency sweeps at 20 °C indicated that all SPS–sugar mixtures were more elastic than viscous with storage moduli (G′) higher than loss moduli (G′′) at all values of frequency with a frequency dependency. Dynamic moduli (G′ and G′′) values increased with the increase in sugar concentration from 10 to 20%. Changes in the dynamic moduli were more pronounced with xylose in comparison to the control (no sugar) and other sugars. G′ values as a function of ageing time (10 h) at 4 °C continuously increased with time during ageing without a plateau region. In general, G′ values of SPS–sugar mixtures during ageing decreased in the following order: pentose (xylose) > hexose (glucose and fructose) > control > disaccharide (sucrose), indicating that the xylose had the greatest ability in retarding retrogradation of SPS.     

Effect of sugars on the mechanical and thermal properties of agarose gels

The present study examines the thermal and mechanical properties of agarose/sugar mixtures using micro-DSC (Differential Scanning Calorimetry) and Dynamic Mechanical Thermal Analyser. In DSC experiments, addition of sugar was reflected in a broad exothermic event compared to sharp transitions generated by the aqueous agarose preparation. At high levels of co-solute, agarose networks show a reduced enthalpic content per gram of the polymer thus arguing for a transformation to a more entropic finely stranded networks of reduced number of junctions zones, the networks exhibited long large deformation properties. At high levels of sugar, agarose samples show a mechanical spectrum that can be modelled according to the WLF/free-volume theory, which requires an entropic lightly cross-linked network.     

Salinity impact on fruit yield,essential oil composition and antioxidant activities of Coriandrum sativum fruit extracts

This study is designed to examine the fruit essential oil composition, the total phenolic amounts and the antioxidant activities in methanolic extracts of Coriandrum sativum under saline conditions. Increasing NaCl levels to 75 mM reduced significantly the fruit yield by 36%. The essential oil yield was 0.30%, based on the dry weight; it increased by 77% and 84% at 50 and 75 mM NaCl, respectively, in comparison to the control. The major constituents were linalool and camphor, whose amounts increased with increasing NaCl concentrations. Antioxidant activities of the methanol extracts were determined by three different test systems, namely DPPH, β-carotene/linoleic acid and reducing power assays. In these three test systems, the highest activity was exhibited in control plants and was reduced significantly with increasing NaCl levels. In control plants, the total phenolic amount was 1.04 mg GAE/g DW which decreased by 43% and 66% at 50 and 75 mM NaCl, respectively.     

Permeability and impact properties of warp-knitted spacer fabrics for protective application

An experimental investigation was carried out to study the effect of interlining material on the comfort and dynamic deformation characteristics of body armour. Suitable plies of interlining materials were selected based on the fabric comfort properties and the impact resistance specified for ballistic application. Kevlar woven fabric was used to block the projectile, and the spacer fabric was used as an interlining material to ensure wearing comfort and for imparting impact resistance. The yarn denier of the middle and bottom layers of the spacer fabrics was maintained constant, and three different deniers were used for the face layer. Three different plies of spacer fabrics were analysed by means of thermophysiological comfort properties to select the suitable interlining material for body armour. The experimental results confirm that the number of plies of spacer fabrics has significant influence on the ballistic armour characteristics than the face layer denier as proved by two-way ANOVA. The substantiated spacer fabric was used as an interlining material, and the depth and area of deformation were analysed. The research findings demonstrated that the three-plied warp-knitted polyester spacer fabric produced better results than single- and five-plied spacer fabrics. One-way ANOVA and Turkey’s HSD also confirmed the influence and interaction of different plies of spacer fabrics.