Sweet potato strips were used as the raw material in this study, and they were impregnated with a 1.5% colloidal solution of gum arabic, guar gum, sodium alginate, and pullulan for vacuum-frying, respectively.The oil and water content, hardness, colour, water distribution, microstructure and porosity, phenolic acid content, and DPPH free radical scavenging ability were adopted as the indicators of vacuum-fried sweet potato strips.This study aimed to explore the effect of coating pretreatment on the quality of vacuum-fried sweet potato strips.Results showed that all the coating agents (gum arabic, guar gum, sodium alginate and pullulan) significantly increased the moisture content of vacuum-fried sweet potato strips and significantly reduced their oil content.Compared to the control sample, the four coating agents significantly reduced the oil content of vacuum-fried sweet potato strips by 17.47%-37.68% and reduced their hardness as well as the colour difference values.The vacuum-fried sweet potato strips coated with sodium alginate had the lowest colour difference values.Compared to the control sample, the proportion of free water in the vacuum-fried sweet potato strips increased from 18.67% to 48.90%, while the proportions of strongly bound and weakly bound water decreased by 18.67%-44.06% and 25.74%-66.09%, respectively.The vacuum-fried sweet potato strips coated with sodium alginate had the lowest content (11.53%) of strongly bound water.Compared with uncoated vacuum-fried sweet potato strips, the four coating treatments significantly reduced the porosity of the vacuum-fried sweet potato strips.Additionally, these coating treatments increased the phenolic acid content and DPPH radical scavenging capacity of the sweet potatoes by 60.68%-130.30% and 25.63%-131.06%, respectively.The vacuum-fried sweet potato strips coated with sodium alginate had the highest phenolic acid content of 1 197.09 μg gallic acid/g sample and DPPH radical scavenging capacity of 2 443.30 μg vitamin C/g sample.Overall, sodium alginate as a coating agent could obtain better frying quality of vacuum-fried sweet potato strips.
[1] XIAO S Z, DAI X B, ZHAO L X, et al.Resequencing of sweetpotato germplasm resources reveals key loci associated with multiple agronomic traits[J].Horticulture Research, 2023, 10(1):uhac234.
[2] ZIERER W, RÜSCHER D, SONNEWALD U, et al.Tuber and tuberous root development[J].Annual Review of Plant Biology, 2021, 72:551-580.
[3] LIU Q C.Improvement for agronomically important traits by gene engineering in sweetpotato[J].Breeding Science, 2017, 67(1):15-26.
[4] DEVI S, ZHANG M, JU R H, et al.Recent development of innovative methods for efficient frying technology[J].Critical Reviews in Food Science and Nutrition, 2021, 61(22):3709-3724.
[5] DIAMANTE L M, SHI S, HELLMANN A, et al.Vacuum frying foods:Products, process and optimization[J].International Food Research Journal, 2015, 22(1):15-22.
[6] ASOKAPANDIAN S, SWAMY G J, HAJJUL H.Deep fat frying of foods:A critical review on process and product parameters[J].Critical Reviews in Food Science and Nutrition, 2020, 60(20):3400-3413.
[7] XIE D F, GUO D B, GUO Z, et al.Reduction of oil uptake of fried food by coatings:A review[J].International Journal of Food Science & Technology, 2022, 57(6):3268-3277.
[8] DEB M, DASH K K.Rheological and mass transport characteristics of hydrocolloid incorporated multilayered wheat flour dough sheet (Khaja) during frying[J].Journal of Food Processing and Preservation, 2022, 46(2):e16227.
[9] ANANEY-OBIRI D, MATTHEWS L, TAHERGORABI R.Chicken processing by-product:A source of protein for fat uptake reduction in deep-fried chicken[J].Food Hydrocolloids, 2020, 101:105500.
[10] 房子蔚, 王雨生, 李鑫, 等.海藻酸钠和低甲氧基果胶抑制油炸甘薯淀粉吸油效果及结构变化[J].粮油食品科技, 2022, 30(3):96-104.
FANG Z W, WANG Y S, LI X, et al.Oil absorption-reducing and structural changes of fried sweet potato starch with the addition of sodium alginate and low methoxyl pectin[J].Science and Technology of Cereals, Oils and Foods, 2022, 30(3):96-104.
[11] YU L, LI J W, DING S D, et al.Effect of guar gum with glycerol coating on the properties and oil absorption of fried potato chips[J].Food Hydrocolloids, 2016, 54:211-219.
[12] DOS SANTOS J S P, LEONEL M, DE JESUS P R R, et al.Hydrocolloid coatings as a pre-frying treatment in the production of low-fat banana chips[J].Horticulturae, 2023, 9(10):1139.
[13] GARGARI A N, ASEFI N, ROUFEGARINEJAD L.Simulation of heat transfer in deep fat frying of foods:An appropriate method for predicting the temperature distribution in a potato model[J].Potato Research, 2022, 65(4):933-957.
[14] SALEHI F, ROUSTAEI A, HASELI A.Effect of surface coating with seeds mucilages and xanthan gum on oil uptake and physical properties of fried potato strips[J].Food Science & Nutrition, 2021, 9(11):6245-6251.
[15] LI Y, LI Z H, GUO Q, et al.Inhibitory effect of chitosan coating on oil absorption in French fries based on starch structure and morphology stability[J].International Journal of Biological Macromolecules, 2022, 219:1297-1307.
[16] SALEHI F, INANLOODOGHOUZ M, AMIRI M.Effect of sonication and edible coating on total phenolic content, antioxidant capacity, and physical characteristics of infrared-dried sweet cherries[J].Journal of Food Processing and Preservation, 2023, 2023(1):5014055.
[17] ZHANG Y, ZHANG T T, FAN D M, et al.The description of oil absorption behavior of potato chips during the frying[J].LWT, 2018, 96:119-126.
[18] 段续, 杨萌萌, 刘文超, 等.怀山药多相态微波干燥微观结构演变[J].农业工程学报, 2024, 40(24):266-273.
DUAN X, YANG M M, LIU W C, et al.Microstructure evolution of Chinese yam in multiphase microwave drying[J].Transactions of the Chinese Society of Agricultural Engineering, 2024, 40(24):266-273.
[19] KUREK M, ŠČETAR M, GALIĆ K.Edible coatings minimize fat uptake in deep fat fried products:A review[J].Food Hydrocolloids, 2017, 71:225-235.
[20] LI Y, BAI X, ZHAO M N, et al.Sodium alginate edible coating to reduce oil absorption of French fries with maintaining overall acceptability:Based on a water replacement mechanism[J].International Journal of Biological Macromolecules, 2023, 236:124042.
[21] SOTHORNVIT R.Edible coating and post-frying centrifuge step effect on quality of vacuum-fried banana chips[J].Journal of Food Engineering, 2011, 107(3-4):319-325.
[22] ZHU R G, SUN S C, LI Y F, et al.Comparative effects of pectin and hydrolyzed pectin coating as pre-frying treatments on acrylamide formation in potato chips[J].International Journal of Biological Macromolecules, 2024, 269:132015.
[23] 陈中爱, 吕都, 刘辉, 等.亲水胶体对真空油炸马铃薯脆片品质的影响[J].食品工业科技, 2019, 40(16):45-49;57.
CHEN Z A, LYU D, LIU H, et al.Effect of hydrophilic colloids on quality of vacuum fried potato crisps[J].Science and Technology of Food Industry, 2019, 40(16):45-49;57.
[24] SALEHI F, GHAZVINEH S, AMIRI M.Effect of basil seed gum coating and ultrasound pretreatment on frying time, oil uptake, hardness, color indexes, and sensory properties of potato slices[J].Ultrasonics Sonochemistry, 2024, 110:107035.
[25] MANOHARAN S, DUBEY P K, SHARMA M.Recent advances in deep-fat frying through pretreatments and edible coating to reduce oil absorption[J].Journal of Food Process Engineering, 2024, 47(8):e14706.
[26] 马雯雯, 李春花, 张建新, 等.油炸食品在贮藏过程中水分和脆性变化研究[J].农产品加工(下半月), 2017(5):11-14;36.
MA W W, LI C H, ZHANG J X, et al.Changes of moisture and brittleness of fried food during storage[J].Farm Products Processing, 2017(5):11-14;36.
[27] BOUAZIZ F, KOUBAA M, NEIFAR M, et al.Feasibility of using almond gum as coating agent to improve the quality of fried potato chips:Evaluation of sensorial properties[J].LWT, 2016, 65:800-807.
[28] YU F, LI Y H, WU Z F, et al.Dehydration of wolfberry fruit using pulsed vacuum drying combined with carboxymethyl cellulose coating pretreatment[J].LWT, 2020, 134:110159.
[29] SU Y, ZHANG M, CHITRAKAR B, et al.Reduction of oil uptake with osmotic dehydration and coating pre-treatment in microwave-assisted vacuum fried potato chips[J].Food Bioscience, 2021, 39:100825.
[30] KHALIL A H.Quality of French fried potatoes as influenced by coating with hydrocolloids[J].Food Chemistry, 1999, 66(2):201-208.
[31] ZHANG J, LIU Y, FAN L P.Effect of pore characteristics on oil absorption behavior during frying of potato chips[J].Innovative Food Science & Emerging Technologies, 2020, 66:102508.
