Treatment of potato chips manufacturing wastewater by electrocoagulation

Treatment of wastewater from potato chips manufacturing by electrocoagulation (EC) was investigated. Experiments were conducted to determine the optimum operating conditions such as electrode type, pH, current density and retention time. Aluminium and iron electrodes were used, and aluminium electrodes were found to be more suitable since it had a higher removal rate of COD, turbidity and suspended solids than the iron electrode. The removal efficiencies of COD and turbidity were high, being 60% and 98%, respectively, with retention time < 40 min. 0.05–1.75 kg (per kg COD removed) of dried sludge was removed. COD removal kinetics during EC process was described by a macro-kinetics model. Results from the kinetic studies showed that the kinetic data fit the second-order kinetic model well. The operating costs investigated in the present study were the energy cost of EC and the material cost due to the consumption of aluminium electrode. Operating costs were varied in the range of 0.48 to 5.42 $/m³ and 0.62 to 6.32 $/m³ wastewater treated at 20–300 A/m² and 5–40 min, respectively. The energy consumption was 4 kWh/m³ for wastewater treated less than 8 min under typical operating conditions.     

Low oil content potato chips produced by infrared vacuum pre-drying and microwave-assisted vacuum frying

The effects of vacuum infrared radiation (VIR) pre-drying on the microwave-assisted vacuum frying (MVF) potato chips were investigated to study its possibility of decreasing the oil content of fried potato chips. The moisture evaporation, oil content, texture, color, surface temperature, shrinkage, and sensory analysis of fried products were evaluated. Results showed that the VIR pre-drying significantly reduced the oil content in MVF products, a decrease from 22.38 to 13.49?g oil/100?g dry solid. The application of VIR pre-drying accelerated the dehydration rate, and increased the mechanical breaking force measured with a texture analyzer with 20–30?min pre-drying. The VIR pre-drying resulted in an increase in the total color change and the shrinkage of MVF potato chips. The sensory analysis showed that the proper duration of VIR pre-drying would achieve a higher consumers’ acceptance. Comparing with the current industrial applications, vacuum frying, and atmospheric deep-fat frying, the combined VIR and MVF technology would be an alternative frying method for producing healthier fried products with less oil content and high quality.     

Palm olein quality parameter changes during industrial production of potato chips

New legislation introduced in South Africa for the quality of used frying oils has resulted in the need to identify quicker, more suitable methods that correlate well with results from two official methods, namely, total polymerized glycerides and total polar components. Oil and product samples were taken at regular intervals during a commercial frying process in palm olein. Oil samples were analyzed for a number of different quality parameters viz. tocopherol content, dielectric constant, total polymerized glycerides, total polar components, tertiary butylhydroquinone (TBHQ) content, anisidine value, Rancimat induction period, and free fatty acid content, and the results statistically compared to results from official methods. Oil was expressed from product stored under accelerated conditions and analyzed for the same quality parameters. Fried product was also subjected to sensory evaluation to measure the degree of oil deterioration and sensory preference. The frying trial was successfully executed with refined, bleached, and deodorized palm olein and the frying oil used to a free fatty acid (FFA) content of 0.41%. Oil and product sampling were done at different FFA value levels. Frying oil quality was verified at the onset of the trial and at regular intervals. The frying oil total polar component value increased to approximately half of the limit set by the official regulation. This point was reached mainly due to the high starting value of the fresh oil. Frying oil total polymerized glycerides increased from below 1% to 2.1%. This increase is negligible when compared to the general trend for polyunsaturated oils. The alternative laboratory methods used for predicting oil quality can be rated as follows: total tocopherol content >dielectric constant >FFA >TBHQ content >anisidine value >Rancimat induction period. The first three methods correlated well with total polar component levels and it is recommended that the dielectric constant and FFA measurements be applied for monitoring oil condition during frying. It is possible that viscosity changes could be used for the monitoring of polyunsaturated frying oils. Evaluation of oil extracted from product revealed a negligible effect of non-oil components on oil quality parameters. The same was observed when product was stored at −10°C and at 37°C.     

Oxidative stability of potato chips determined by Rancimat

During recent years the Rancimat apparatus has been used extensively to determine the stability of fats and oils. Most stability tests for fat-containing foods are performed on the extracted oil. The objective of this research was to observe the behavior of potato chips in the racimat without oil extraction. Determinations were carried out at 110°C and 20 L/hr air flow. The curves for the ground chips were completely different from those obtained with extracted oils. Curves for fresh potato chips showed two inflection points after approximately 5 and 20 hr, respectively. Sensory analyses (odor score) of samples withdrawn from the Rancimat after 0, 5, 10, 20 and 25 hr showed significant differences (P < 0.01). An odor score of 5 was considered the rejection point, and was equivalent to 10.8 hr and corresponded to 150 μs of electric conductivity. At this point, the curves started to level off between the first and second inflection points. Curves obtained with potato chips stored at 25°C for 2, 4, 6, 8, 10 and 12 wk showed the same basic pattern, although prolonged storage corresponded with lower induction time. Correlation of induction values between ground potato chips and extracted oil was high (r > 0.87). From these results, it seems that it is possible to estimate the oxidative stability of fatcontaining foods without prior extraction. Presented at 81st AOCS Annual Meeting, Baltimore, MD, 1990.     

瓶级聚酯切片质量特性对制品透明性的影响

对分子质量、IPA含量、热稳定剂含量及水含量等质量指标不同的瓶级聚酯切片进行注塑,制成标准片,检测透明性,发现这几项质量指标对制品的透明性有不同程度的影响,为调优瓶级聚酯切片质量指标、改善PET制品透明性提供依据。     

Antioxidative effect of olive oil deodorizer distillate on frying oil and quality of potato chips

The antioxidative effect of unsaponifiable matter from olive oil deodorizer distillate on the stability of sunflower oil during frying and on the quality of potato chips were studied. Physical and chemical characteristics of sunflower oil samples with or without different concentrations of unsaponifiable matter were examined during frying at 180°C for ten consecutive days. The addition of 1% of unsaponifiable matter to sunflower oil showed the highest effect in retarding the oxidation deterioration of oil during frying of potato chips. This protective effect was attributed to high levels of squalene, Δ-avenasterol, and tocopherols. During ten frying days, the amount of squalene decreased to 79% and both tocopherols and Δ-avenasterol to 69% in frying sunflower oil. Oil absorbed by potato chips and the characteristics of the oil extracted from potato chips before and after three months of storage were determined. The amount of oil absorbed by potato chips ranged from 37.3 to 39.3% during frying. The unsaponifiable fractions remaining in the frying medium showed protective effects on the rate of oxidation of the oil extracted from potato chips. The uptake of unsaponifiable matter by chips was the highest during the first frying day. Chips with high amounts of squalene, tocopherols, and sterols showed highest antioxidative stability during storage for three months at ambient temperature. Potato chips fried in sunflower oil treated with 1% unsaponifiable matter showed a bright yellow colour, moderate crispness, high score flavour, and were well accepted by panelists. These data of sensory evaluation supported the results of chemical analyses of oil extracted from fresh and stored chips.     

食用油瓶用PET切片的研制开发

介绍了食用油瓶用聚酯切片的品质指标,特殊要求及存在的问题。阐述了生产食用油瓶用聚酯切片的方法,即:调整工艺、加入共聚第三组分IPA、控制添加剂的用量等。提供了一种改性聚酯的新生产工艺。     

Sensory and chemical stability of tortilla chips fried in canola oil,corn oil,and partially hydrogenated soybean oil

The effects of canola, corn, partially hydrogenated soy (PHS), partially hydrogenated canola (PHC), and low-linolenate canola (LLC) oils on sensory and chemical attributes of tortilla chips were determined initially, after Schaal storage for 8 and 16 d (S8 and S16), and after practical storage for 16 and 24 wk (P16 and P24). Fresh chips were similar to each other in characteristic and off-odors/flavors, except that PHC chips had the lowest characteristic and highest off-odor/flavor. All S8 chips had similar lower (P<0.001) characteristic and greater off-odor/flavor scores than hidden reference chips, but PHC chips had a more intense off-odor than did LLC chips. After S16, canola chips had the lowest (P<0.001) characteristic and highest off-odor/flavor; all other chips were similar. At P16, canola, PHC, and LLC chips had slightly higher (P<0.001) characteristic odor/flavor scores than other chips. After P16 and P24, all stored tortilla chips had lower characteristic odor/flavor scores than hidden reference chips. Rancid, painty, buttery odor/flavor, and bitter flavor notes were detected in Schaal and practically stored chips. Stored chips from all oils were similar in color and crispness. The peroxide value and thep-anisidine value for oils extracted from Schaal-stored chips tended to support panelist data; results from similar analyses of practically stored chips did not. Peroxide values andp-anisidine values for stored used frying oils and the corresponding sensory data for stored chips generally did not agree. Results indicate considerable potential for increasing use of canola oil products for frying tortilla chips.     

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.     

粉末固定化白腐菌处理焦化废水的研究

以木屑为载体固定化白腐菌对焦化废水进行处理,其对COD的去除率明显高于白腐菌菌丝和木屑的混合物.研究表明,白腐菌对焦化废水有较好的处理效果,3 d COD的去除率可达84.89%.固定化的白腐菌降解焦化废水的适宜pH为5.5-7.0,最佳pH为6.5;适宜温度为25~35℃,最佳温度为30℃.     

铸铁屑与过氧化氢联合降解硝基苯废水的研究

采用铸铁屑与过氧化氢联合降解硝基苯废水,研究了初始溶液的pH值、H2O2用量、铸铁屑用量、初始硝基苯浓度等因素对硝基苯降解进程的影响。结果表明,常温下用铸铁屑和过氧化氢降解硝基苯废水的优化条件是:针对500 mL的80 mg/L的硝基苯废水的降解,初始硝基苯废水调节pH值为2.5时,30%的H2O2用量为15 mL,铸铁屑用量为1 g时,反应时间120 m in,硝基苯的降解率可达93%以上。     

The preparation of activated carbons from chips of oil palm trunk catalysed by ZnCl2/CO2: Surface area and porosity studies

Activated carbons were prepared by ZnCl₂/CO₂ activation of the chips of oil trunk. The surface area and the nature of the porosity of the resulting activated carbons were found to be related to the concentration of the impergnated zinc solution to the precursor. It is possible to prepare activated carbons with a fairly high surface area (more than 2000 m² g^?1) from chips of oil palm trunk.     

Optimization of Vacuum Microwave Predrying and Vacuum Frying Conditions to Produce Fried Potato Chips

The effects of vacuum microwave predrying and vacuum frying conditions on the quality of vacuum-fried potato chips were studied. Both the moisture content and oil content of potato chips decreased with increasing vacuum microwave predrying time. During vacuum frying, the moisture content of potato chips decreased with increasing frying temperature and time, while the oil content increased. Statistical analysis with response surface regression showed that the moisture content, oil content, and breaking force of potato chips were significantly (P<0.05) correlated with vacuum microwave predrying time, frying temperature, and frying time. Based on surface responses and contour plots, optimum conditions were vacuum microwave predrying time of 8–9 min, vacuum frying temperature of 108–110°C, and vacuum frying time of 20–21 min.     

Optimization of some parameters on agglomeration performance of Zonguldak bituminous coal by oil agglomeration

In this study, the optimization of some parameters on agglomeration performance of Zonguldak bituminous coal by oil agglomeration was discussed. A three-level Box-Behnken design combining with a response surface methodology (RSM) and quadratic programming (QP) were employed for modeling and optimization some operations parameters on oil agglomeration performance. The relationship between the responses, i.e., grade and recovery, and four process parameters, i.e., amount of oil, agitation time, agitation rate and solid content were presented as empirical model equations for both grade and recovery on oil agglomeration. The model equations were then optimized individually using the quadratic programming method to maximize both for grade and recovery within the experimental range studied. The optimum conditions were found to be 14.61% for amount of oil, 8.94 min for agitation time, 1554 rpm for agitation rate and 5% for solid content to achieve the maximum grade. The maximum model prediction of 0.650 grade at these optimum conditions is higher than any value obtained in the initial tests conducted. Similarly, the conditions for maximum recovery were found to be 20.60% for amount of oil, 5 min for agitation time, 1800 rpm for agitation rate and 19.48% for solid content with a prediction of 96.90% recovery, which is also higher than any other recovery obtained in the initial tests conducted.     

Characterisation of some Australian oil shale using thermal, X-ray and IR techniques

Thermogravimetric analysis (TGA), Diffuse Reflectance Infrared Fourier Transforms Spectroscopy (DRIFTS) and X-ray diffraction (XRD) were used in conjunction to characterise oil shale samples from an Australian Tertiary oil shale deposit. Results from these techniques were compared with conventional Modified Fisher Assay (MFA) data. DRIFTS and TGA results showed clear correlations with each other as well as with the MFA values. DRIFTS results indicated that most of the kerogen is in aliphatic hydrocarbon form. It was evident from TGA analysis that the weight loss in the 450-550 °C temperature region has a strong and direct correlation with the amount of oil in the samples, as determined by the MFA method. Calibration curves were generated in which oil content can be predicted from TGA and DRIFTS data. The combination of TGA and DRIFTS is mostly useful in examining organic matter in oil shale while DRIFTS and XRD combination is useful in examining the minerals phases. XRD and DRIFTS showed good agreement in identifying the presence of minerals such as quartz, clay and carbonates. Combination of these three techniques can provide an alternative and inexpensive method to the MFA analysis in determining the kerogen content, while overcoming the limitations of each other.     

Variation of kerogen content and mineralogy in some Australian tertiary oil shales

Oil shale is a potential alternative source of petroleum products. The processes of retorting oil shale and refining shale oil are both affected by the composition of the parent rock. Mineralogical and geochemical data obtained from two bore holes in Queensland oil shale deposits are presented and discussed here. The data includes the variation with depth of mineralogy, ash content, moisture content and kerogen content. A strong correlation of hydrogen and organic carbon, and higher H/C ratios suggest that organic matter is present mainly as aliphatic compounds. Pyrite was identified as the major source of sulphur. This may provide some possibilities for easier removal of sulphur before the oil shale is processed.     

Optical and mechanical properties of cocona chips as affected by the drying process

The effect of the application of a pre-osmotic treatment to obtain hot air dried cocona (Solanum sessiliofurum Dunal) chips was studied. The drying kinetics and the optical and mechanical properties of cocona chips obtained by the combined method of osmotic dehydration and hot air drying (OD + HAD) and by only hot air drying (HAD) were compared. Samples were dried by hot air at 60 °C. For the combined method, they were pre-dried to a moisture content of 75 g_water/100 g, immersed in a 55 °Brix sucrose solution at 25 °C for 48 min. The pre-osmodehydration applied did not influence the subsequent hot air drying kinetics, resulting in a final product with 0.055 ± 0.005 g_water/g_cocona. The optical properties of OD + HAD chips were more favorable, exhibiting a smaller color change with respect to the fresh fruit (±15 units) than the HAD samples (±23 units). On the other hand, the OD + HAD chips presented more fracture peaks than HAD ones, this related with a structure with a higher degree of crispness, a very desirable property for a chip product.     

钛系聚酯的性能、可纺性及纤维加工中色相变化研究

采用自制的钛系催化剂合成聚酯,以同一聚合釜合成的常规锑系聚酯为对比样,系统考察钛系聚酯的切片质量指标、纺丝性能、后加工性能、纤维色相方面的变化等。结果表明,相同装置上合成的钛系聚酯的纺丝、后加工性能与常规锑系聚酯未见差异,完全可以满足纤维生产要求;非锑聚酯应用于生产纤维时纤维的成型加工（纺丝、牵伸）等可以改善钛系聚酯切...     

Phenolic compounds and some quality parameters of pumpkin seed oil

Pumpkin seed oil has become a recognized source of phenolic compounds. The main aim of this paper was to evaluate the concentration of phenolic compounds and their extraction from pumpkin seed oil. The total phenolics content (TPC) measured in the pumpkin seed oil samples ranged from 24.71 to 50.93 mg GAE/kg of oil. The individual phenolics were tyrosol, vanillic acid, vanillin, luteolin and sinapic acid. Hexane and acetone were the best solvents for the washing step, and methanol for the elution of the phenolics in the solid‐phase extraction (diol‐SPE), whereas bleaching caused a significant increase in the TPC obtained (24.5–30.7%). Additionally, some other oil characteristics were evaluated. The mean oxidative stability of the oils (OSI) was around 4 h, with 5.43 h for the most stable oil. The maximum antioxidant capacity measured by the reduction of the DPPH radical was 62%, which was comparable to 0.16 mM Trolox equivalent. The color of the oil was expressed by L*a*b* coefficients and its hue and saturation. Whereas all samples had similar lightness, their rates of green, red, yellow and blue color were different. Moreover, TPC correlated negatively with lightness, b* and saturation (–0.49, –0.48, and –0.43), and positively with a* and hue (0.58 and 0.52).