Data from: Free Amino Acids and Sugars in Fifteen Sweetpotato Genotypes: Effects of Curing and Storage on Acrylamide Formation in Fried Chips

The objective of the study was to measure changes in sugars and free amino acids in 15 sweetpotato genotypes before curing, after curing, and over 10 months of storage to investigate the effects on acrylamide formation.The data are of the raw sweetpotatoes (sugar and free amino acids) and chip attributes (oil, acrylamide, color).Materials and Processing: Sweetpotatoes grown in duplicate blocks using conventional practices at the NCDA Research Station in Clinton, NC, USA. Harvested roots were cured (30°C and 85-90% RH) for 7 days, stored at 13-16°C and 80-90% RH for 2, 4, 6, 8, and 10 months. At each timepoint, 7 to 12 sweetpotatoes from each genotype were washed, peeled, and sliced 1.5 mm thick then fried at 157 °C in canola oil for 3 minutes. Raw slices and fried chips were stored at -20 °C until analysis. Raw slices were freeze dried then ground into a powder.Dry matter: Dry matter was determined by drying at 105 °C for 24 h.Chip fat and moisture contents: Chip moisture and fat contents were measured with a Maran NMR analyzer (Resonance Instruments Ltd., Witney, UK).Chip color: Hunter L*, a*, and b* values of crushed chip samples were measured using a DP‐900 Colorimeter (Hunter Associates Lab, Reston, VA, USA)Sugar Contents: One gram of powder was extracted with 20 mL of boiling ethanol, vortexed, incubated held for 15 min, centrifuged, decanted into 50 mL volumetric flask, then repeated. Glucose, fructose, sucrose, and maltose were separated isocratically using 150 mM NaOH at 1 mL/min on a Dionex CarboPac PA-1 (4 x 250 mm) with guard column (4 x 50 mm) and detected with an Antec Scientific (Alphen a/d Rijn, NL) Decade II electrochemical detector. Fried chip sugars were measured in the same matter but after chips were defatted with hexane.Free Amino Acid Analysis: One gram of powder was extracted with 5 mL of 0.1 M HCl, vortexed, incubated at 4 °C for overnight, then centrifuged. The supernatant was used for total free amino group analysis and individual amino acid quantification. For individual quantification, 250 µL of extract was mixed with 250 µL of internal standards in acetonitrile, vortexed, centrifuged, then filtered in a 0.5 mL, 0.22 µm Ultrafree-MC-GV centrifugal filter tube. Amino acids in filtrate were measured using a Shimadzu Nexera-2 UHPLC system with LCMS-8030 plus using electrospray ionization. They were separated using an Atlantis Silica HILIC column (4.6 mm × 100 mm, 3 μm particle size) (Waters Corporation, Midford, MA, USA) at 35 °C and 0.6 mL/min mobile phase A (85% acetonitrile with 0.15% formic acid and 10 mM ammonium formate) and mobile phase B (water with 0.15% formic acid and 10 mM ammonium formate) using the following gradient profile: 0 to 9.6% B from 0 to 3 min; 9.6 to 27% B from 3 to 7 min; 27% B from 7 to 8 min; 27 to 37% B from 9 to 10.5 min; then re-equilibrated with 0% B from 10.5 to 19 min. Glycine was separated isocratically with 0.5% acetonitrile,0.1% acetic acid in water at 0.5 mL/min and 35°C using an Atlantic dc18 column (4.6mm × 100 mm, 3 μm particle size) (Waters Corporation, Midford, MA, USA). Total free amino groups Free amino groups were measured by the o-phthalaldehyde (OPA) method (Church et al., 1983) with and external standard curve of L-leucine dissolved in 0.1 M sodium tetraborate buffer at a pH of 9.0.Acrylamide measurements: One gram of ground chip material was spiked with 0.2 mL of d3-labelled-acrylamide internal working standard (10 μg/ml in 10 mM formic acid) then extracted with 19 mL of 10 mM formic acid by vortexing for 3 min. Carrez I and Carrez II reagents (0.5 mL of each) were added, then centrifuged at 0°C. 1.5 mL of the clarified aqueous supernatant was loaded onto a preconditioned Oasis HLB SPE cartridge followed by a preconditioned BondElut Accucat SPE cartridge. Acrylamide was measured using the same LC-MS/MS system separated isocratically using 10 mM formic acid at a flow rate of 0.3 mL/min at 25 °C on an Atlantis T3 column (150 mm x 4.6 mm, 3 μm).<br>Abbreviations and termsBlock: Growing block; Dup: Replicate from the same block; Acn: Acrylamide, GABA: gamma-aminobutyric acid; RS: Reducing sugars; CbRt: cubic root transform; fw: fresh weight; dw: dry weight

本研究旨在测定15个甘薯基因型在愈伤处理前、愈伤处理后以及10个月贮藏期内的糖类与游离氨基酸变化，以探究其对丙烯酰胺（acrylamide）生成的影响。本数据集包含生甘薯样本的糖类、游离氨基酸数据，以及薯片样品的品质指标（油脂含量、丙烯酰胺含量、色泽）。

材料与处理流程：
甘薯采用双重复区组种植，栽培方式符合常规农业规范，种植地点为美国北卡罗来纳州克林顿市的北卡罗来纳州农业厅（NCDA）试验站。收获后的块根先进行7天的愈伤处理（温度30℃，相对湿度85%~90%），随后置于13~16℃、相对湿度80%~90%的环境中分别贮藏2、4、6、8及10个月。在每个取样时间点，取每个基因型的7~12个甘薯块根，经清洗、去皮后切成1.5mm厚的薄片，随后在157℃的菜籽油中油炸3分钟。生薯片薄片与油炸薯片均置于-20℃条件下保存，直至后续分析。生薯片薄片经冷冻干燥后研磨成粉末。

干物质含量：采用105℃烘干24小时的方法测定干物质含量。

薯片脂肪与水分含量：采用英国威特尼市共振仪器有限公司（Resonance Instruments Ltd.）生产的Maran核磁共振波谱仪（NMR analyzer）测定薯片的水分与脂肪含量。

薯片色泽：采用美国弗吉尼亚州雷斯顿市亨特联合实验室（Hunter Associates Lab）生产的DP-900色差仪，测定粉碎后薯片样品的Hunter L*、a*、b*色度值。

糖类含量测定：称取1g粉末样品，加入20mL沸腾乙醇进行提取，经涡旋混匀、静置孵育15分钟、离心后，将上清液转移至50mL容量瓶中，重复上述提取步骤。采用含150mM氢氧化钠的等度洗脱体系，流速1mL/min，在带保护柱（4×50mm）的Dionex CarboPac PA-1色谱柱（4×250mm）上分离葡萄糖、果糖、蔗糖与麦芽糖，并通过荷兰阿尔芬市安泰克科学公司（Antec Scientific, Alphen a/d Rijn, NL）的Decade II电化学检测器进行检测。油炸薯片的糖类含量测定采用相同流程，但需先使用正己烷对薯片样品进行脱脂处理。

游离氨基酸分析：称取1g粉末样品，加入5mL 0.1M盐酸溶液进行提取，经涡旋混匀后于4℃条件下孵育过夜，随后离心。取上清液用于总游离氨基基团分析与单个氨基酸定量检测。针对单个氨基酸定量：取250μL提取液与250μL乙腈内标溶液混合，经涡旋混匀、离心后，通过0.5mL、0.22μm的Ultrafree-MC-GV离心过滤管进行过滤。采用岛津Nexera-2超高效液相色谱（UHPLC）系统搭配LCMS-8030三重四极杆质谱仪，以电喷雾电离模式对滤液中的氨基酸进行检测。色谱分离采用Atlantis Silica HILIC色谱柱（4.6mm×100mm，粒径3μm，美国沃特世公司（Waters Corporation），马什菲尔德市），柱温35℃，流动相A为含0.15%甲酸与10mM甲酸铵的85%乙腈溶液，流动相B为含0.15%甲酸与10mM甲酸铵的水溶液，洗脱梯度如下：0~3min，B相从0升至9.6%；3~7min，B相从9.6%升至27%；7~8min，维持27% B相；9~10.5min，B相从27%升至37%；10.5~19min，以0% B相进行柱平衡。甘氨酸采用等度洗脱方式分离，流动相为含0.1%乙酸的0.5%乙腈水溶液，流速0.5mL/min，柱温35℃，色谱柱为Atlantic dc18柱（4.6mm×100mm，粒径3μm，美国沃特世公司）。总游离氨基基团：采用邻苯二甲醛（OPA）法（Church等，1983）进行测定，以溶于pH9.0的0.1M四硼酸钠缓冲液中的L-亮氨酸作为外标标准曲线。

丙烯酰胺含量测定：称取1g研磨后的薯片样品，加入0.2mL氘代丙烯酰胺（d3-labelled-acrylamide）内标工作液（10μg/mL，溶于10mM甲酸溶液），随后加入19mL 10mM甲酸溶液，经涡旋混匀3分钟完成提取。加入Carrez I与Carrez II试剂（各0.5mL），于0℃条件下离心。取1.5mL澄清后的水相上清液，上样至预先活化的Oasis HLB固相萃取（SPE）小柱，随后再上样至预先活化的BondElut Accucat固相萃取小柱。采用美国沃特世公司的Atlantis T3色谱柱（150mm×4.6mm，粒径3μm），以10mM甲酸为等度洗脱流动相，流速0.3mL/min，柱温25℃，结合前文所用的LC-MS/MS系统完成丙烯酰胺的定量检测。

缩写与术语：
Block：种植区组
Dup：同一区组的重复样本
Acn：丙烯酰胺（acrylamide）
GABA：γ-氨基丁酸（gamma-aminobutyric acid）
RS：还原糖（Reducing sugars）
CbRt：立方根变换（cubic root transform）
fw：鲜重（fresh weight）
dw：干重（dry weight）