Potato Strips Research Articles

Quality attributes of French fries as affected by different coatings, frozen storage and frying conditions

Potato strips treated with different coatings (Carboxymethyl cellulose (CMC), pectin, agar and chitosan) at concentrations of 1 and 2% then fried for various durations (5, 7, 9, 11 and 13 minutes) were investigated for organoleptic and other quality parameters. Strips were submerged in coating solutions for 5 seconds prior deep fat frying. Frying for 11 and 13 minutes gave the most significantly accepted fries while all coating treated strips obtained lower sensory quality scores and the concentrations used did not significantly affect sensory parameters of strips (p<0.05). Coatings reduced the amount of oil absorbed by strips by 12.93% (pectin), 11.71% (CMC), 8.28% (chitosan) and 5.25% (agar). Coating treatments and concentration significantly improved moisture retention of strips (p<0.05). Strips treated with hydrocolloids at 1% and fried for 11 minutes revealed that texture and yellowness (b*) values were not significantly different from the control strips. Lightness (L*) values of treated strips were similar to the control strips except chitosan treated strips (p<0.05). Redness (a*) values of all coated strips were not significantly different from the control strips except agar coated strips. In another study, potato strips were semi-fried at 170 ± 5°C for 2 minutes followed by quick air blast freezing at -32°C for 20 min and stored at -18°C for 6 months. The effect of frozen storage duration on quality parameters was monitored every month. Data revealed that peroxide values (PV) initially increased and later decreased with elongation of storage duration. Free fatty acid (FFA), thiobarbituric acid (TBA) and p -anisidine ( p -AV) values significantly increased with storage duration (p<0.05). Total oxidation (totox) values increased with storage duration. The CMC coating treatment did not significantly lower PV, FFA and TBA values while p -AV values were significantly lowered during frozen storage (p<0.05).

Changes in the textural and thermal properties of batter coated fried potato strips during post frying holding

Post frying conditions play a very important role in consumer acceptability of French fries. During post frying holding time, from when fried potatoes are removed from a fryer to when consumed, texture of the product dramatically changes. Therefore, it is important to understand how and why these changes happen. In this study, the effect of different batter formulations and post frying holding time (with and without using a heat lamp) on fat and moisture distribution, textural and thermal properties of fried potato strips was studied. Moisture content ranged from 3.90 to 5.32 (in core region), 0.54 to 1.19 (in crust region), and 1.96 to 2.89g/g db (in whole potato strips). Fat content of the core, crust and whole potato strip regions ranged between 0.01–0.03, 0.14–0.25, and 0.07–0.15g/g db, respectively. A slight migration of moisture from the core to crust regions was observed under heat lamp holding, but this did not affect the total moisture content. Potato samples that were not kept under heat lamp showed lower hardness than samples kept under heat lamp. Brittleness values of potato samples increased from 0 to 10min heat lamp duration and after that it significantly decreased. It was found that glass transition temperature of the samples was also affected by batter formulation and heat lamp duration.

Oil spots and moisture pocket re-distributions between crust and core regions of potato strips during post-frying holding

Abstract The effect of different batter formulations and post frying holding time (with and without using a heat lamp) on oil spots and moisture pocket redistributions on the surface crust and in the core regions of fried potato strips was studied. Potato strips were fried at 180 ± 2 °C in canola oil and then kept under a heat lamp for different time intervals. Fractal dimension was used to measure the surface roughness of the samples. The fractal values ranged between 2.63 and 2.69. Image processing technique was applied to study the oil spots on the surface and moisture pocket distributions in the core regions. The results indicated that the number of oil spots and moisture pockets were indirectly related to the area. Keeping the samples for longer time under a heat lamp reduced the number of big oil spots, whereas increased their mean area.

In situ quantitative 1H nuclear magnetic resonance spectroscopy discriminates between raw and steam cooked potato strips based on their metabolites

A direct quantitative proton nuclear magnetic resonance spectroscopy method was developed for the measurement of saccharides, organic acids and amino acids in potato (Solanum tuberosum L.) tuber filaments, a complex gel-like food matrix. The method requires minimal sample preparation. It is thus a faster alternative compared to liquid sample matrices, as well as an extension to methods analyzing only selected metabolites in the sample. The samples in this study were either raw or steamed potato strips that were either measured as D2O extracts or directly without extraction or derivatization steps (in situ technique). A total of 22 compounds were identified in extracts and 18 in potato strips. Of these, 20 compounds were quantifiable in potato extracts and 13 compounds in potato strips. The effect of thermal processing was reflected in the profile of analyzed compounds. One example was fumaric acid, which was completely lost in steamed samples in both measurement techniques. Additionally, the content of γ-aminobutyric acid in steamed potato strips was lower. In potato extracts, the contents of additional 7 compounds were statistically different. The raw and steamed samples separated into two groups with multivariate models both in extracts and potato strips, and these groups were linked to changes in aforementioned compounds. These results demonstrated that the in situ quantitative 1H NMR technique is a useful tool to analyze potato metabolites. This technique could be further applied to any gel-like complex matrix, meaning that lengthy sample pretreatment could be skipped.

A novel bacterial type II l-asparaginase and evaluation of its enzymatic acrylamide reduction in French fries

This study reports the identification of a novel bacterial type II l-asparaginase, abASNase2, from Aquabacterium sp. A7-Y. The enzyme contains 319 amino acids and shared 35% identity with Escherichia coli type II l-asparaginase (EcAII), a commercial enzyme trademarked Elspar® that is widely used for medical applications. abASNase2 had high specific activity (458.9U/mg) toward l-asparagine, very low activity toward l-glutamine and d-glutamine and no activity toward d-asparagine. The optimal enzymatic activity conditions for abASNase2 were found to be 50mM Tris-HCl buffer (pH 9.0) at 60°C. It was very stable in the pH range of 7.0–11.0 and exhibited up to 80% relative activity after 2h below 40°C. The Km and kcat of abASNase2 were 1.8×10−3M and 241.9s−1, respectively. In addition, abASNase2’s ability to remove acrylamide from fried potato strips was evaluated. Compared to untreated potato strips (acrylamide content: 0.823±0.0457mg/kg), 88.2% acrylamide was removed in the abASNase2-treated group (acrylamide content: 0.097±0.0157mg/kg). These results indicate that the novel l-asparaginase abASNase2 is a potential candidate for applications in the food processing industry.

A First Approach of Using Ultrasound as an Alternative for Blanching in Vacuum-Packaged Potato Strips

The effect of ultrasound (US) (40 kHz, 200 W, 3 min), blanching (85 °C, 3.5 min), and the combination of both methods was evaluated on the quality of vacuum-packaged potato strips stored at 3 ± 1 °C for up to 10 days. For this study, two cultivars of potatoes were assessed. For blanched Agata samples, the lightness (L*) decreased over 12 % (p < 0.05). Moreover, their hue increased up to 100, obtaining lesser yellow potato strips. In contrast, US did not affect the hue values. The losses of firmness of blanched potato strips were notable (35 % for Agata and 51 % for Agria), whereas US did not change this property (p < 0.05). Nevertheless, no significant differences were found in the total starch content at 10 days. Agata and Agria showed different metabolic behaviors of sucrose in the refrigerated storage. Therefore, Agria cultivar retained better color after frying. These results suggest that US had less impact on color and improve the firmness in vacuum-packaged potato strips with no added chemicals.

Hydrocolloids of Date Pits Used as Edible Coating to Reduce Oil Uptake in Potato Strips During Deep-Fat Frying

In the current study, a rapid and simple method including the use of aqueous solution containing hydrocolloids and phenolics extracted from date pits (HSDP) was used, for the first time, as a natural edible coating to reduce oil uptakein potato strips during deep-fat frying. The results indicated that HSDP solutions contained 8.2-17.9 g/kg hydrocolloidsand 0.31-1.95 g/kg phenolics. Samples of coated potatoes were prepared by different HSDP concentrations (0.5-6%, w/v) followed with/without drying before deep-fat frying. Analysis of deep-fat fried samples indicated that 4% HSDP coating reduced oil uptake by 77.7% which is higher than that of other hitherto published reports. Texture and colour analysis showed adequate brittleness, crispiness and lightness of HSDP coated fries compared to common methyl cellulose coated fries. Sensory analysis reflected also that HSDP coating maintained the overall acceptability of potato products. Therefore, the proposed HSDP coating is a rapid, economic and easy-to-operate process at homes for preparing acceptable low-fat potato fries that widely used not only in our society but also all over the world.

Influence of β-cyclodextrin and Sodium Chloride Addition to Oil on Shrinkage Kinetics during Frying of Potato Strips

Influence of β-cyclodextrin and Sodium Chloride Addition to Oil on Shrinkage Kinetics during Frying of Potato Strips

Combined Effects of Gamma Irradiation and Blanching Process on Acrylamide Content in Fried Potato Strips

Potato tubers were irradiated in 60Co gamma station at different doses in order to investigate the effect of gamma irradiation on acrylamide formation in fried potato strips. Acrylamide content due to the irradiation treatment was reduced by 20–54% compared to a control after frying the irradiated tubers. While apply a blanching process, using warm tap water, to potato strips before frying has decreased acrylamide by 61%. A combination of gamma irradiation and a blanching process, which was applied in this work, showed a maximum decrease in acrylamide formation to reach 78% in fried potatoes.

Functionality of Coatings with Salep and Basil Seed Gum for Deep Fried Potato Strips

AbstractWe investigate the efficiency of using a coating made from novel hydrocolloid basil seed gum (BSG), salep, and a mixed solution of BSG and salep as well as oil origin (canola or palm olein) to reduce oil absorption in deep‐fried potato strips. We also evaluate the coating pick up, its effect on moisture content, frying yield value of fried potatoes and flow behavior of the coating suspensions. Flow curves show that all the studied suspensions are pseudoplastic and have shear thinning characteristics. The most effective coating formulations were 0.5 % BSG and 1.5 % salep. For these formulations, maximum oil uptake reduction was 28.8 and 28.7 % for potato strips compared to uncoated samples; the increase in moisture content was 29.1 and 17.5 %, respectively. Furthermore, the increase in moisture content resulted in an increase in frying yield up to 16.62 % for 0.5 % BSG. The oil type significantly (p &lt; 0.05) influenced oil uptake.

Frying of Potato Strips Pretreated by Ultrasound-Assisted Air-Drying

Ultrasound is an emerging technology in various areas of food processing, preservation and safety. Due to its high dehydration efficiency, application of ultrasound prior to frying may hand in promising results in reducing oil uptake. The objective of this study was to examine the effect of ultrasound as well as the simultaneous effect of ultrasound and pre-drying on oil uptake of fried potato strips. Ultrasound pretreatments were performed at 28 and 40 kHz and drying pretreatments were conducted at 80C for 8 and 15 min. Then, frying process was carried out at 150, 170 and 190C. Results showed that, compared to control, oil uptake of samples pretreated with both ultrasound and drying significantly decreased (P < 0.05). It was concluded that at all the frying temperatures, samples pretreated with ultrasound had lower oil uptake in comparison with control samples. Practical Applications Deep-fat frying process is broadly used for both domestic and industrial purposes. High-power (low-frequency) ultrasound modifies food properties by inducing mechanical, physical and chemical or biochemical changes. Ultrasound techniques are relatively cheap, simple and energy saving. It has been demonstrated that decreasing the initial moisture content of raw material reduces oil uptake in the fried product. Regarding high dehydration efficiency of ultrasound, this study provides information on the possibility of using ultrasound-assisted air-drying as a pretreatment prior to frying, in order to investigate oil uptake of fried potato strips.

Quality of the pre-cooked potato strips processed by Radiant Wall Oven

Steam processing was paired with the Radiant Wall Oven (RWO) to produce reduced-fat baked potato strips. Par-fried frozen potato strips, having 5 × 1 × 1 cm3 dimensions, were pre-cooked in steam chamber for 75 or 90 s. Then, steam-processed potato strips were heated in RWO at different temperatures: 450 °C for 3 or 3.5 min, at 500 °C for 2.5 or 3 min, at 550 °C for 1.5 or 2 min. Instrumental and sensory quality characteristics of RWO processed pre-cooked potato strips were investigated and compared to deep-fat fried samples at 177 °C for 3 min. RWO baked pre-cooked potato strips at 500 °C for 3 min, regardless of steam processing time, were similar to control in terms of texture, chroma, shrinkage and yield, yet contained 86.8% less fat. A trained panel indicated that texture of the potato strips, baked in RWO at 500 °C for 3 min after steam processing for 90 s, was not significantly different than that of the control samples. Finally, consumer panel indicated 51.2% acceptability and 35% willingness to purchase the RWO-baked pre-cooked potato strips. However, acceptability of the RWO-baked pre-cooked potato strips rose to more than 75% when fat content and corresponding calories were revealed.

Influence of the frying process and potato cultivar on acrylamide formation in French fries

Acrylamide formation during the production of French fries is attributed to Maillard reactions from reducing sugars and asparagine and is dependent on the frying temperature. Low reducing sugars content in potatoes has been recommended to produce fried potato products. However, the influence of the complexity of the potato medium in the chemical reactions that promote the acrylamide formation during deep frying are not well understood. In this study, three potato cultivars (Kennebec, Red Pontiac and Agria) commonly used for fried potato products were evaluated to determine the relationships between the precursors of acrylamide in the fresh potato tubers and the properties of the fried potato strips with the acrylamide content after frying. Frying experiments were conducted at three conditions (time-temperature) to obtain French fries of similar visual colour. Acrylamide formation increased with frying temperature but different behaviour was observed between cultivars. For Red Pontiac, a remarkably increase in acrylamide content was found at 170 °C (∼40%) together with the increase in colour. However, lower oil uptake and higher moisture content was obtained as temperature increase. Significant positive correlations were observed between the acrylamide level and the reducing sugars and sucrose content on fresh potatoes (0.652, 0.699, p ≤ 0.01, respectively). The acrylamide content obtained in Agria cultivar may be obtained from the hydrolysis of sucrose during the frying process. In fried potato strips, positive significant correlation was found between the shear force and acrylamide (0.749, p ≤ 0.01). The significant correlations obtained between colour, and texture, colour and oil uptake and texture and acrylamide content indicate the intrinsic relationship between the properties of the fried potato strips and the acrylamide content.

Role of MC Compounds at Less of Oil Absorption of French Fries Potato

Methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) were used in coating formulations to reduce oil uptake in deep-fat frying potato strips and dough discs. MC coatings were more effective in reducing oil uptake than HPMC ones. The effect of plasticizer addition (sorbitol) was also evaluated. The best formulations were 1% MC and 0.5% sorbitol for fried potatoes and 1% MC and 0.75% sorbitol for dough discs. For these formulations, oil uptake reduction was 40.6 and 35.2% for potato strips and dough discs compared to the uncoated samples; the increase in water content was 6.3 and 25.7%, respectively. Non-significant differences in texture of coated and uncoated samples were observed. Although instrumental color differences were detected, all samples were accepted by the non-trained panel. 2002 Elsevier Science Ltd. All rights reserved.

Biochemical characterization of a novel l-asparaginase from Bacillus megaterium H-1 and its application in French fries

ABSTRACT A novel ansZ gene, encoding a putative l -asparaginase II from Bacillus megaterium H-1 (BmAase), was cloned and expressed in Escherichia coli. The recombinant enzyme showed high activity (44.7 IU/mg) with negligible glutaminase activity and was purified to homogeneity using one-step nickel-affinity chromatography. The molecular weight of BmAase was 39.63 kDa by MALDI-TOF MS. The optimum pH and temperature for BmAase activity were 7.0 and 40 °C, respectively. The enzyme was stable in the pH range of 5.0–8.0 and exhibited more than 70% and 55% retention of activity following 12 h of incubation at 60 and 70 °C, respectively. The melting temperature of the protein determined by DSC was 51.3 °C. The KM and Vmax values of BmAase were, respectively, 0.80 mM and 1.58 IU/μg for its natural substrate l -asparagine. Acrylamide formation upon frying of potato strips treated with BmAase was about 92% lower than in untreated potato strips. These results reveal the potential of this enzyme for use in the food processing industry.

مدل سازی سینتیک افت رطوبت قطعات سیب زمینی پیش تیمار شده با اولتراسوند و مایکروویو در طی فرایند سرخ کردن عمیق

مدل سازی فرایند سرخ کردن در جهت آگاهی از روابط بین متغییرهای مختلف، می تواند گامی مناسب در جهت بهبود کیفیت محصول باشد. در این پژوهش، اثر پیش تیمار اولتراسوند تحت فرکانس های 28 و 40 کیلوهرتز به مدت 15 دقیقه و پیش تیمار مایکروویو با توان های 3 و 6 وات بر گرم به مدت 10 دقیقه بر میزان رطوبت سیب زمینی سرخ شده در درجه حرارت های 150، 170 و 190 درجه سانتی گراد به مدت 60، 120، 180 و 240 ثانیه مورد بررسی قرار گرفت. برازش داده های تجربی افت رطوبت نمونه ها در طی فرآیند سرخ کردن با استفاده از شش مدل تجربی پیشنهادی و قانون فیک انجام شد. نتایج نشان داد که هر دو پیش تیمار اولتراسوند و مایکروویو در کلیه سطوح مورد استفاده، میزان رطوبت نهایی نمونه ها را به طور معنی داری در سطح احتمال 5 درصد کاهش دادند. همچنین، با افزایش دما، میزان رطوبت نمونه های سیب زمینی به شکل غیرمعنی دار در سطح احتمال 5 درصد کاهش یافت. از طرف دیگر، با افزایش زمان فرایند، میزان رطوبت نمونه ها به طور معنی دار و بصورت نمایی کاهش پیدا کرد. همچنین، مدل های پیشنهادی در این پژوهش، با داشتن ضریب تبیین بالا (2R( و ریشه میانگین مربعات خطا (RMSE) پایین، به خوبی داده های تجربی را برازش نمودند. ضریب انتشار مؤثر رطوبت برای نمونه های مختلف در دامنه 8-10×57/3 الی 8-10×08/11 متر مربع بر ثانیه به دست آمد. اعمال پیش تیمارهای اولتراسوند و مایکروویو موجب افزایش ضریب انتشار مؤثر رطوبت و کاهش انرژی فعال سازی نمونه ها شدند.

Effect of CMC levels on amount of oil uptake of potato French fries

The objective of this study was to apply coating on potato at levels 1.5 % of carboxy methyl cellulose (CMC) in order to reduce oil uptake in fried potato strips. With increase of consumer conscious, demand for low fat products has been increased. Concentration aqueous suspension of CMC with 1 and 1.5% were provided with batch number OC445231401 with code RG20 6 NE, UK. It was tested to select appropriate formulation for coating application. Potato varieties of local Greek were coated and uncoated samples were fried in temperature 180 °C for 10 minute with local sunflower oil. The obtained results showed that: 1) The effect of coating with CMC due to their barrier properties, lead to decrease in potato weight loss of strips during frying and by respect to the % oil uptake at coated samples with 1.5% CMC were less than blank sample and CMC 1%. Percentage of weight loss potato was 24 and 12% for CMC 1% and CMC 1.5%. Thermal conductivity coefficients were 552 and 560 watt/mk for above levels of CMC. But this different were not significant, while, Crust of thickness was siginificant and 4) the best coating were 1.5% CMC for low fat french fries potato production.

Effect of Ratio Oil to Potato on Amount of Oil uptake and Quality of Potato French Fries

In deep fat fried products health should be addressed to meet consumer demand .the soft and moist interior together with crispy crust are desirable characteristics of most fried food. In this study the effect of ratio oil to potato on amount of oil uptake of potato strips at two size were investigated. Results showed that ratio oil to potato 20:1 lead to increase in potato loss of strips during frying among other ratios (33% oil uptake %). Oil to potato 10:1 had the lowest amount of fat content (24% oil uptake %). By this study, the highest and lowest loss weight percent were 44% and 34% which related to ratio 20 and 10 respectively. Significant differences in texture of several ratio were observed. Ratio 20 was the most texture of fried potato, but from view of oil uptake %, ratio of 10 was the best for two sizes of french fries potato.

The effect of biological (yeast) treatment conditions on acrylamide formation in deep-fried potatoes

Effects of biological (yeast) treatments on acrylamide formation in deep-fried potatoes were studied. Potato chips were subjected to yeast fermentation prior to deep-frying to lower the level of reducing sugars and to reduce the amount of acrylamide. The solid-liquid ratio, fermentation temperature, and quantity of added yeast were studied. Optimum conditions for decreasing reducing sugar contents were a 1:4 solid-liquid ratio, a fermentation temperature of 37°C, and addition of 0.5% yeast. Potato strips treated under optimum conditions had 70% less acrylamide than control group chips after deep-frying. Yeast fermentation treatments are an effective way to reduce acrylamide formation in fried potatoes without influencing product quality.

Consumer Acceptability and Quality Evaluation of Potato Strips Baked in a Radiant Wall Oven

Instrumental and sensory quality of potato strips baked in a radiant wall oven was evaluated and compared to deep-fat fried and conventional oven baked samples. Even though radiant wall oven baked potato strips had one-fourth the fat content of the deep-fat fried samples, there was no significant difference in chroma, cutting and puncture force of radiant wall oven baked and deep-fat fried samples. Consumer acceptability of radiant wall oven baked potato strips was 65.7 and 85.7% before and after revealing the nutrition facts, respectively. Both were lower than acceptability of deep-fat fried samples. However, 36.5% of consumers were willing to purchase radiant wall oven baked samples.