The hurdle effect of osmotic pretreatment and high‐pressure cold pasteurisation on the shelf‐life extension of fresh‐cut tomatoes

Tomatoes are perishable products due to the activity of microorganisms and endogenous enzymes. The objective was to produce cut tomatoes with extended shelf life, using the combined hurdle effect of osmotic pretreatment (OD) and high pressure (HP), instead of a conventional one‐step thermal process. Samples were processed in a multicomponent osmotic solution at 35 °C, subsequently cold‐pasteurised in pack at 600 MPa and stored at 5–15 °C. Quality deterioration during isothermal and nonisothermal storage was kinetically modelled. Both OD process and OD‐HP combined process caused an increase in lycopene content that was well retained. Texture, colour and flavour of treated samples were evaluated as similar to fresh, with OD‐HP samples showing better retention during storage. Being microbiologically stable, shelf life of OD‐HP samples was limited by sensory deterioration, whereas OD samples were rejected due to eventual microbial growth. Shelf life of OD and OD‐HP samples was estimated at 77 and 181 days, respectively, at 5 °C.     

High-efficiency continuous-flow microwave heating system based on metal-ring resonant structure

Continuous-flow microwave heating has been widely applied in liquid food processing, and the heating efficiency relies heavily on the dielectric property of loads with fixed dimensions in a certain cavity. Specifically, rectangular waveguides are widely applied, and straight pipes are usually inserted through the center of rectangular waveguides. However, maintaining high efficiency is always challenging since the dielectric property will vary with temperature. Therefore, a simple and cheap resonant structure is proposed in this paper to maintain high heating efficiency for loads with a large range of relative permittivity in both modeling and experiment. First, the straight pipe surrounded by metal rings in a rectangular waveguide with a short circuit terminal was introduced to concentrate the electric field in the pipe. Then, a multiphysics model was established to calculate the energy efficiency of various load permittivity. The position of the short circuit terminal and the dimensions of the metal ring were further optimized. Finally, energy efficiency experiments of different aqueous ethanol solutions and liquid foods and point temperature rise experiments of continuous-flow water were carried out, and the results showed that the proposed structure can be used to maintain high energy efficiency over large dielectric dynamic ranges compared with the conventional microwave heating system based on rectangular waveguides. Moreover, the effect of different parameters, the pipe permittivity, the pipe wall thickness and the metal ring gap, on the heating efficiency was discussed to show the robustness of the proposed structure.     

Determination of biofilm production by Candida tropicalis isolated from hospitalized patients and its relation to cellular surface hydrophobicity,plastic adherence and filamentation ability

Candida tropicalis is an emerging virulent species. The aim of this study is to determine the biofilm‐forming ability of 29 strains of C. tropicalis isolated from inpatients, and to examine its relation with other virulence factors such as cellular surface hydrophobicity (CSH), immediate (15 min, IA) and late (24 h, LA) plastic adherence and filamentation ability. The study was performed in parallel using two incubation temperatures – 37 and 22 °C – to determine the effect of growth temperature variations on these pathogenic attributes of C. tropicalis. Biofilm formation (BF) was measured by optical density (OD) and by XTT reduction (XTT); Slime index (SI), which includes growth as a correction factor in BF, was calculated in both methods. All strains were hydrophobic and adherent – at 15 min and 24 h – at both temperatures, with higher values for 22 °C; the adhered basal yeast layer appears to be necessary to achieve subsequent development of biofilm. Filamentation ability varied from 76.2% of strains at 37 °C to 26.6% at 22 °C. All C. tropicalis strains were biofilm producers, with similar results obtained using OD determination and XTT measurement to evaluation methods; SI is useful when good growth is not presented. BF at 37 °C was similar at 24 h and 96 h incubation; conversely, at 22 °C, the highest number of biofilm‐producing strains was detected at 96 h. CSH is an important pathogenic factor which is involved in adherence, is influenced by the filamentation of yeast, and plays a critical role in BF. Copyright © 2013 John Wiley & Sons, Ltd.     

The effect of osmosis pretreatment on hot‐air drying and microwave drying characteristics of chili (Capsicum annuum L.) flesh

Chili flesh pretreated with or without osmotic dehydration (OD) was dried in the hot‐air drying (AD) oven at 50–80 °C or in the microwave drying (MD) oven at 60–180 W. Results showed that the samples osmotically treated in mixed solution (10% salt + 50% sucrose) had the best dehydration effect as compared with single salt or sugar solutions. During the drying process, osmotically treated samples had one falling‐rate period and their effective moisture diffusivities (D_eff) showed a rapidly linear increase with the decrease in moisture content, while directly drying samples showed a three‐phase falling‐rate period and their D_eff increased gradually at the initial period and then rapidly at the final period. When the moisture content decreased, the activation energy increased gradually; however, for AD after OD, it decreased. Among all the processes, MD at 60 W after OD presented the largest vitamin C retention rate and the best colour difference, needing less drying time.     

Effectiveness of Rinse Water during In‐Place Cleaning of Stainless Steel Pipe Lines

The 1st step of any Clean‐In‐Place (CIP) operation is a prerinse with water. The purpose of this step is to remove the bulk of food material remaining in the processing lines after production period has ended. It is known that this prerinse step can be a very water intensive process. The objective of this investigation was to measure the influence of CIP parameters (flow characteristics, water temperature, and contact time) on the effectiveness of prerinse water in removing dairy‐based deposits from stainless steel pipe surfaces and to compare the rinse effectiveness of unused to reused rinse water. A pilot‐scale CIP system was operated to rinse 304 stainless steel pipe sections of 3 different pipe diameters. The velocity of the rinse water was varied from 0.72 to 2.26 m/s. The rinse water temperatures were 22 °C, 45 °C, and 67 °C. The contact times between rinse water and deposited film were 20 and 60 s. Rinse effectiveness was expressed as the ratio of the amount of protein residue removed from the pipe surface during rinsing, as compared to the magnitude of the initial protein deposit. The rinse effectiveness varied from 73.1% to 94.9% for the range of the CIP parameters investigated. High velocities of rinse water provided a higher level of rinse effectiveness. Increasing the rinse water temperature from 23 °C to 45 °C improved rinse effectiveness significantly (P < 0.05). This impact was not significant when the water temperature was increased from 45 °C to 67 °C and at higher rinse water velocities. Similarly, longer contact time provided less improvement in rinse effectiveness at higher temperatures and velocities as compared to lower temperatures and velocities. There were no significant differences in rinse effectiveness when comparing reused and unused water (normal tap water) within the range of velocities evaluated.     

带织物层叠缠绕玻璃钢管的设计与缠绕成型

采用仿形织造方法织造带织物,并用该带织物层叠缠绕生产玻璃钢管道是一种新方法。在缠绕成型过程中,为了使管道的成型性良好,需要对缠绕角度、经纱长度、织物幅宽等进行设计,同时选择成型效果好的织物组织。试验结果表明:圆直管道预成型织物的缠绕角取决于织物幅宽、缠绕层数和管道直径;织物的经纱长度不等,按照一定的规律随缠绕层数的增加而增加;2/2斜纹组织织物的成型效果较好。     

PREDICTING THE CLEANABILITY OF MIX-PROOF VALVES BY USE OF WALL SHEAR STRESS

The purpose of this work was to predict the outcome of a practical cleaning test for closed food‐process equipment by examining wall shear stress distributions in the equipment estimated from Computational Fluid Dynamics (CFD) simulations. Such predictions make evaluation and improvement of hygienic design of equipment prior to prototype production possible. To do this, knowledge of hydrodynamic cleaning effects is required. The importance of hydrodynamics was shown by cleaning tests on a mix‐proof valve (MPV) and a straight pipe. The MPV was easier to clean than a straight pipe. An explanation to this was sought in this work by the idea of a critical wall shear stress. A radial flowcell (RFC) was used for prediction of the critical wall shear stress. Prediction of cleanability in the MPV was performed by comparison of wall shear stress estimated in the MPV by CFD to the critical wall shear stress found in the RFC. Cleanability was under‐predicted by the use of simulated wall shear stress compared with cleanability estimated from actual cleaning trials.     

Process optimisation and physicochemical characterisation of enzymatic hydrolysates of proteins from co‐products of Atlantic Salmon (Salmo salar) and Yellowtail Kingfish (Seriola lalandi)

The aim of this study was to develop an enzymatic hydrolysis process of protein co‐products for two major commercial fish species in Australia: Atlantic salmon (AS) and Yellowtail kingfish (YTK). The outcomes are to produce high protein recovery of fish protein hydrolysates within controlled molecular weight ranges that display enhanced physicochemical properties of oil binding and emulsification. Three enzymes (Flavourzyme, Neutrase and Alcalase) were applied to processing co‐products. Protein recovery and physicochemical properties were evaluated with increasing hydrolysis time from 30 min to 180 min and ratio of enzyme to substrate (E/S) from 0.5% to 3.0%. In order to achieve a product with optimum emulsifying capacity (50 ± 0.6 m² g^?1), an E/S ratio of 0.6–1.3% Flavourzyme was applied for 30–111 min with a protein recovery of 55%; in order to achieve a product with optimum oil‐binding capacity (8.3 ± 0.3 g oil g hydrolysates^?1), an E/S ratio of 2.3–3.0% Flavourzyme was applied for 25–64 min with a protein recovery of 70%. YTK protein hydrolysates were further membrane‐fractionated into five fractions (>100 kDa, 50–100 kDa, 30–50 kDa, 10–30 kDa and <10 kDa), and of these, the 10–30 kDa exhibited the best properties of oil binding (19 ± 0.3 g oil g hydrolysates^?1) and emulsification (57 ± 0.7 m² g^?1). These results demonstrate the importance of enzymatic hydrolysis of seafood co‐products into high‐value ingredients for food products and processing.     

Influence of ultrasound pretreatments on diffusion coefficients,texture and colour of osmodehydrated sweet potato (Ipomea batatas)

The moisture and solute diffusivities, texture and colour of sweet potato pretreated in distilled water with ultrasound (UD), osmotic dehydration without ultrasound (OD) and osmotic dehydration with ultrasound (UOD) were investigated to determine the effects of ultrasound on osmodehydrated sweet potato. The moisture and solute diffusivities of all the pretreatments ranged from 2.89 to 4.95 × 10^?10 and 1.17 to 1.67 × 10^?10 m² s^?1, respectively. The moisture diffusivity of samples treated in UOD was significantly (P < 0.05) higher than that of OD and UD by 30.82% and 41.62%, respectively. Compared to the fresh sample, the firmness of samples treated in OD and UOD was reduced by 83.53% and 92.47%, respectively. UD increased the brightness (L*) and reduced the redness (a*) of sweet potato, while UOD enhanced the yellowness (b*) and chroma (C*) of sweet potato. The sweet potato samples treated in UOD had the highest total colour difference (ΔE).     

PILOT PLANT FOR OSMOTIC DEHYDRATION OF FRUITS: DESIGN AND EVALUATION

This work proposes a pilot scale equipment for osmotic dehydration (OD) of apple cubes that consists of a novel agitation‐immersion device, a bag filter and a vacuum evaporator to conduct simultaneously the OD process, filtration and reconcentration of the osmotic solution (OS). The functional method analysis was used to design the pilot plant. Apple cubes (～1 cm³) were dehydrated using a 60 ° Brix sucrose syrup OS at 50C and a syrup/fruit ratio of 5. OD was conducted either with or without reconcentration of the OS. During the OD process particles of fruit were eliminated from the OS by filtration and the OS concentration was kept at 60 ° Brix by reconcentration in the evaporator. A comparison of the dehydration parameters of apple cubes obtained at pilot scale to those obtained at laboratory scale was done to evaluate the performance of the pilot equipment. The results show that the proposed set‐up can be suitable for commercial production of osmodehydrated fruits.     

Volatile Retention and Morphological Properties of Microencapsulated Tributyrin Varied by Wall Material and Drying Method

Butyric acid is an important short‐chain fatty acid for intestinal health and has been shown to improve certain intestinal disease states. A triglyceride containing 3 butyric acid esters, tributyrin (TB) can serve as a source of butyric acid; however, the need to target intestinal delivery and mitigate unpleasant sensory qualities has limited its use in food. Microencapsulation, the entrapment of one or more cores within a matrix, may provide a solution to the aforementioned challenge. This research primarily focused on the influence of (1) wall material: whey and soy protein isolate (WPI and SPI, respectively) and gamma‐cyclodextrin (GCD), (2) wall additives: inulin of varying chain length, and (3) processing method: spray or oven drying (SD or OD, respectively) on the morphological properties and volatile retention of TB within microcapsules. SPI‐based microcapsules retained significantly less (P < 0.001) TB compared to WPI‐based microcapsules as measured by gas chromatography. The inclusion of inulin in the SD WPI‐based microcapsules increased (P < 0.001) TB retention over WPI‐based microcapsules without inulin. Inulin inclusion into WPI‐based microcapsules resulted in a smoother, minimally‐dented, circular morphology as compared to noninulin containing WPI‐based microcapsules as shown by scanning electron microscopy. GCD and TB OD microcapsules retained more (P < 0.001) TB (94.5% ± 1.10%) than all other WPI, WPI‐inulin, and GCD TB SD microcapsules. When spray dried, the GCD‐based microcapsules exhibited (P < 0.001) TB retention than all other microcapsules, indicating the GCD may be unsuitable for spray drying. These findings demonstrate that microencapsulated TB in GCD can lead to minimal TB losses during processing that could be utilized in functional food applications for intestinal health.     

Evaluation of process conditions on osmotic dehydration and quality indexes of pumpkin (Cucurbita moschata) and further polymeric film selection for packaging and refrigerated storage

We studied the influence of composition and concentration of solutions and product size on mass transfer kinetics during Anco pumpkin osmotic dehydration (OD). Once optimal conditions were determined, samples packed in commercial polymeric films were microbiologically analysed during refrigerated storage. The optimal OD time was 3 h, when the efficiency index WL/SG (water loss/solid gain) was stabilised. At this time, 1.0 and 1.5 cm cubes presented the highest index value (about 11) in binary solution (sucrose 55°Bx). WL was higher in 1.0 cm cubes for each dehydrating ternary salt solution tested, and no significant differences in firmness were observed with Calcium Lactate addition. Thus, optimal condition for OD in ternary solutions was 180 min and 55°Bx – 2% NaCl. Microbiological determinations were done for dehydrated (55°Bx without/with 2% NaCl) and untreated samples, packaged in different polymeric films. The combination with lowest mesophilic and psychrophilic counts at day 10 was: samples dehydrated with ternary solution of sucrose-salt packed in Polypropylene film.     

Osmotic dehydration of carrot tissue enhanced by pulsed electric field,salt and centrifugal force

The osmotic dehydration (OD) kinetics of carrot disc untreated and treated by pulsed electric field (PEF) was studied under centrifugation (2400 × g), stirring (250 rpm) and with a salt addition (NaCl/sucrose solutions 0%/65%, 5%/60% and 15%/50%). The PEF intensity was E = 0.60 kV/cm and the treatment duration was t_PEF = 0.05 s (500 rectangular monopolar pulses each of 100 μs). The water loss (WL), solids gain (SG) and water loss/solids gain ratios (WL/SG) were evaluated in the binary (sucrose + water) and ternary (sucrose + salt + water) solutions at the temperature of 20 °C during 4 h. The mass ratio of sample to solution was 1:3. The PEF treatment and salt addition enhanced the OD kinetics. WL and SG were increased under centrifugation (centrifugal OD) and under stirring (static OD). The centrifugal field enhanced the WL, however, decreased the SG comparing to the static OD. Therefore, the static OD has advantages for the higher SG (confectionary adds), while the centrifugal OD is better appropriated if the WL should be increased and the solids (sugar) uptake should be limited (dietetic products).The two-exponential kinetic model fitted well to experimental data for both static and centrifugal OD. The correlation coefficient was R² = 0.982–0.999 and the standard error was 5–10%.     

Effect of Ultrasound-Assisted Osmotic Dehydration as a Pretreatment on Deep Fat Frying of Potatoes

The objective of this study was to investigate the possibility of using ultrasound-assisted osmotic dehydration (UAOD) as a pretreatment prior to frying and to study its effects on the quality of fried potatoes. The quality parameters, moisture content, oil uptake, color, texture, and microstructure of fried potatoes, were chosen. Quality of fried potatoes treated with UAOD was also compared with the ones treated with osmotic dehydration (OD). Potato slabs (40 × 40 × 7 mm) were pretreated with different osmotic solutions (15 % sodium chloride and 15 % sodium chloride/50 % sucrose solutions) at different temperatures (25, 45, and 65 °C) with and without ultrasonic waves for different treatment times. The pretreatment conditions which are OD for 90 min and UAOD for 30 min using 15 % sodium chloride/50 % sucrose solution were applied prior to frying at 170 °C for 2, 4, and 6 min. UAOD reduced the oil content of fried potatoes by 12.5 % (db) as compared to untreated fried potatoes at the end of frying. There was no significant difference between OD and UAOD in reduction of oil uptake in fried potatoes. However, UAOD was found to have the advantage of improving the color of French fries. In addition, it shortened the pretreatment time of OD by about 67 %. Cell structure of fried potato was damaged in the presence of pretreatments of OD and UAOD.     

Effects of Ultrasound on Mass Transfer Kinetics,Structure, Carotenoid and Vitamin C Content of Osmodehydrated Sweet Potato (Ipomea Batatas)

The effects of ultrasound pretreatments on mass transfer kinetics, microstructure, carotenoid and vitamin C contents of sweet potato were investigated. Sweet potato samples were treated in distilled water with ultrasound (DWU), osmotic dehydration without ultrasound (OD) and ultrasound-assisted osmotic dehydration (UOD). Samples were subjected to ultrasound probe of 2 cm diameter, frequency of 28 kHz at 300 W maximum power at different pretreatment times of 20, 30, 45 and 60 min. The Azuara model used in this study fitted the experimental data well with high coefficient of correlation ranging from 0.92 to 0.98, low values of chi-square (<0.6), root mean square error (<0.9) and percent mean relative deviation (<10%). The results showed that UOD significantly (p < 0.05) had the highest mass transfer coefficient and equilibrium value for water loss and solid gain, compared to DWU and OD. DWU had no significant effect on the structure of sweet potato samples, while UOD had the highest effect on the structure. The samples treated in OD had the highest carotenoid retention compared to DWU and UOD at all pretreatment times. However, ultrasound enhanced the retention of vitamin C (>70%) in sweet potato samples treated in DWU and UOD.     

Water Diffusion and Concentration Profiles During Osmodehydration and Storage of Apple Tissue

The objective of this work was to study the mobility of water and sucrose during osmotic dehydration and storage of apple tissue and to conduct an analysis of the behavior of the effective diffusion coefficients determined from concentration profiles. Osmotic dehydration (OD) of apple was carried out at 40°C for 1 h, and the solution: sample ratio was 20:1 (w/w). Samples of 20-mm diameter were extracted from the dehydrated apple immediately after the OD process and after 4 and 24 h of storage at 25 °C. Moisture of these samples and soluble solids content were analyzed. Our results showed, after 1 h of OD, the outer layer of the apple sample lost 0.37 kg water/kg apple and gained 0.30 kg sucrose/kg apple. These values decreased toward the internal layers of the apple. A fine layer of greatly dehydrated cells was formed on the surface around the sample, which determined the mass transfer rate in the whole tissue. Smaller mass transport rates were observed in the development of concentration profiles during storage. Diffusion coefficients obtained for the outer layer after 1 h of OD were 1.53 × 10⁻¹⁰ and 1.05 × 10⁻¹⁰ m²/s for water and sucrose, respectively. The analysis of compositional profiles developed during osmodehydration was a useful tool to get a better understanding of the changes in the water activity of the outer layer of the apple tissue.     

超高分子量聚乙烯管道在疏浚输油工程上的应用前景

中国的输油与疏浚工程技术正在飞速发展,迫切需要高性能、高强度、多功能、高安全性及符合绿色环保要求的输油与疏浚管道,以实现石油开采与输送的高效率与低成本,满足疏浚工程中大型多功能挖泥船的强度安全与高效率的需要。超高分子量聚乙烯(ultra-high molecular weightpolyethylene,简称UHMWPE)是由乙烯、丁二烯单体在催化剂的作用下-聚合而成的平均分子量大于150万的热塑性工程塑料。目前,世界范围内UHMWPE的分子量可达150万～1050万,结晶度为65%～85%,密度为0.92～0.96g/cm3。它具有高强度、高耐磨、高耐冲击、高耐寒、自润滑、不结垢、耐腐蚀、耐环境应力开裂性好、高抗内压强度、轻便等优点,可取代钢管和昂贵的合金钢管、不锈钢管,用于疏浚与输油这两大要求极严格的工程领域,实现这两大领域在材料上的突破与创新。     

Application of High Hydrostatic Pressure as a Pretreatment for Osmotic Dehydration of Banana Slices (Musa cavendishii) Finish-Dried by Dehumidified Air Drying

The process variables high hydrostatic pressure (HHP; 100–500 MPa), sucrose concentration (30–70 °Brix), immersion time (5–9 h) and immersion temperature (30–70 °C) were optimised to yield maximum water loss (WL), minimum solid gain (SG), minimum water activity (a _w) and minimum browning index (BI) during osmotic dehydration (OD) of banana slices (Musa cavendishii) pretreated by HHP using response surface methodology. The pressure-treated samples showed significantly higher WL and SG during OD (p?<?0.05), which was attributed to the rupture of cell wall with applied pressure, making the cells more permeable, also evident from the scanning electron micrographs of the banana tissue. The optimised operating conditions were: HHP of 200 MPa for a dwell time of 5 min at room temperature (26 °C), sucrose concentration of 60 °Brix, immersion time of 5 h and immersion temperature of 40 °C. A study of the concentration profiles during OD revealed no appreciable increase in SG and WL after 4 h; hence, immersion time was reduced to 4 h. The optimised product developed was dried to a moisture content of 15 % (wet basis) in a dehumidified air dryer at an air temperature of 40, 55 and 70 °C with a fixed air velocity of 3.8 m/s and relative humidity maintained at 20 %. The final dried product was analyzed for total soluble solids content, BI and a _w. A drying temperature of 55 °C was found to give superior quality OD banana slices in terms of reduced bulk, improved flavour, decreased a _w (<0.60), and reduced dehydration time and energy using HHP as a pretreatment.     

R‐Index Measure of Microencapsulated Tributyrin in Gamma‐Cyclodextrin Influenced by Drying Method

Microencapsulation is commonly used in the food industry for a variety of purposes including added ingredient functionally and taste‐masking for those ingredients with negative sensory qualities. Tributyrin (TB), a source intestinally‐essential butyric acid, possesses negative aroma (cheesy, fecal) and taste (bitter) qualities. This has significantly limited its use in food applications for the potential improvement of intestinal health. Utilizing spray drying and low‐temperature oven drying, microcapsules containing TB were produced using whey (WPI), WPI and inulin, and gamma‐cyclodextrin (GCD). To determine how microcapsule formulation and drying method affected the perception of TB relative to a control, microencapsulated and free TB were added to an infant formula system and evaluated using the rating method to determine R‐index measures. Pooled R‐index measures (α = 0.01, 2‐tailed, and n = 170) indicated that the only microcapsule not significantly different from the control (R‐index below 57.95%) was the GCD and TB oven dried (GCT OD) microcapsule. All other WPI, WPI–inulin, and GCD and TB spray‐dried (GCT SD) microcapsules were all significantly different from the control. Average individual R‐index results indicated that all microcapsules in infant formula, except for GCT OD, were significantly different (P < 0.01) from the control formula but not from free TB. Spray drying may create microcapsules with surface TB and disturb the GCD–TB complex, allowing free, and surface TB to be perceived by the panelists. The GCT OD microcapsule has the potential to be used for the potential oral treatment of intestinal disorders in functional food applications without the negative sensory qualities of TB.     

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.