Glycoalkaloids (α-chaconine and α-solanine) contents of selected Pakistani potato cultivars and their dietary intake assessment

Glycoalkaloids (α-solanine and α-chaconine) are naturally occurring toxic compounds in potato tuber (Solanum tuberosum L.) that cause acute intoxication in humans after their consumption. Present research was conducted to evaluate α-chaconine, α-solanine, and total glycoalkaloids (TGAs) contents in the peel and flesh portions by high-performance liquid chromatography method in selected Pakistani potato cultivars. The α-solanine content varies 45.98 ± 1.63 to 2742.60 ± 92.97 mg/100 g of dry weight (DW) in peel and from 4.01 ± 0.14 to 2466.56 ± 87.21 mg/100 g of DW in flesh. Similarly, α-chaconine content varied from 4.42 ± 0.16 to 6818.40 ± 211.07 mg/100 g of DW in potato peel and from 3.94 ± 0.14 to 475.33 ± 16.81 mg/100 g DW in flesh portion. The TGA concentration varied from 177.20 ± 6.26 to 5449.90 ± 192.68 mg/100 g of DW in peel and from 3.08 ± 0.11 to 14.69 ± 0.52 mg/100 g of DW in flesh portion of all the potato cultivars tested. All the potato cultivars contained lower concentration of TGA than the limits recommended as safe, except 2 cultivars, that is FD8-3 (2539.18 ± 89.77 mg/100 g of DW) and Cardinal (506.16 ± 17.90 mg/kg). The dietary intake assessment of potato cultivars revealed that Cardinal, FD 35-36, FD 8-3, and FD 3-9 contained higher amount of TGA in whole potato, although FD 8-3 only possessed higher content of TGA (154.93 ± 7.75) in its flesh portion rendering it unfit for human consumption. Practical Application: This paper was based on the research conducted on toxic compounds present in all possible potato cultivars in Pakistan. Actually, we quantify the toxic compounds (glycoalkaloids) of potato cultivars through HPLC and their dietary assessment. This paper revealed safety assessment and their application in food industries especially potato processing.     

The influence of thermal process of coloured potatoes on the content of glycoalkaloids in the potato products

Potato products made from potato varieties with coloured flesh (red and blue-fleshed potatoes) may be an interesting alternative to traditional products. The purpose of this study was to determine the influence of peeling, cooking and frying of red and blue-fleshed potato tubers on the content of glycoalkaloids (α-solanine and α-chaconine) in processed potato products. The material taken for the study consisted of seven coloured potato varieties. French fries and crisps were prepared from two potato variety: Rosalinde and Blue Congo. The content of total glycoalkaloids (TGA) in raw material before and after peeling, in cooked unpeeled and peeled potatoes and also in fried potato products have been determined by HPLC method.     

Polyphenol and glycoalkaloid contents in potato cultivars grown in Luxembourg

The polyphenol (phenolic acids, flavanols and flavonols) and glycoalkaloid (α-chaconine and α-solanine) contents of potato tubers grown in Luxembourg were analyzed by UPLC–DAD and HPLC–MS/MS separately in peel (approx. 2 mm), outer (approx. 1 cm) and inner flesh. Polyphenol contents decreased from the peel via the outer to the inner flesh and differed among the cultivars. The cultivars Vitelotte and Luminella had the highest polyphenol contents (5202 and 572 μg/g dry weight (DW) in the outer flesh), whereas Charlotte and Bintje had the lowest contents (19.5 and 48.0 μg/g DW). Chlorogenic acid and its isomers (neo- and cryptochlorogenic acid) were the major polyphenols. Glycoalkaloid contents were highest in the peel and lowest in the inner flesh, values in the flesh were below guideline limits in all cultivars. In conclusion, potatoes contribute to the daily intake of polyphenols and their consumption, thereby, may have positive effects on health.     

高效液相色谱串联质谱法检测马铃薯及马铃薯粉中α-茄碱和α-卡茄碱含量

建立了高效液相色谱-串联质谱同时测定马铃薯及马铃薯粉中α-茄碱与α-卡茄碱含量的方法。样品采用10%乙酸水溶液匀浆提取3 min,马铃薯粉提取液经Bond Elut C18 SPE柱净化后,采用C18色谱柱分离,液相色谱串联质谱仪检测。结果表明,α-茄碱和α-卡茄碱在0.01~1.00 μg/mL范围内线性关系良好,相关系数分别为0.9998和0.9997。马铃薯和马铃薯粉在低、中、高三个添加浓度范围内,回收率在90.0%~110%之间,相对标准偏差在1.6%~5.0%之间。马铃薯中α-茄碱和α-卡茄碱的定量限分别为0.80和0.42 μg/kg,马铃薯粉中α-茄碱和α-卡茄碱的定量限分别为25和14 μg/kg(S/N=10)。本方法简单快速,灵敏度高,重复性好,适用于马铃薯及马铃薯粉中的α-茄碱和α-卡茄碱检测。     

The influence of French fries processing on the glycoalkaloid content in coloured-fleshed potatoes

French fries made from coloured-fleshed potatoes may be interesting alternative to the traditional snacks for consumers. However, potatoes contain glycoalkaloids (TGA), so potato tubers and obtained fried snacks should be subjected to comprehensive examination. The aim of this study was to determine the effect of different stages of French fries processing on the content of TGA (α-solanine and α-chaconine) in the red- and blue-fleshed potatoes, in semi-products and ready-to-eat products. It was stated that during the processing of French fries prepared from coloured-flesh potato varieties significantly decreased the content of TGA (α-solanine and α-chaconine) in the samples obtained at different stages of the process compared to the raw material. Potatoes with blue-fleshed of Vitelotte variety and red-fleshed of Highland Burgundy Red variety can be used to French fries processing due to their low content of TGA (in unpeeled and peeled potatoes). However, Blue Congo variety with blue-fleshed should not be applied to French fries processing, because of high TGA content in raw material and first of all in peeled potatoes flesh. The peeling process of coloured-fleshed potatoes decreased in TGA content on average by about 50 %, cutting process on average by about 53 %, whereas blanching on average by about 58 % compared with the raw material. The highest decrease in TGA content was caused by frying process. The mean values were about 97.5 % in ready-to-eat French fries. In French fries after I and II steps of frying, the ratio α-solanine to α-chaconine was lower (1.0:2.0) than in unpeeled potatoes (1.0:2.3).     

马铃薯不同品种各器官糖苷生物碱累积规律研究

为探究马铃薯块茎、茎、叶中糖苷生物碱累积规律,本研究选用云南省2个主栽马铃薯品种丽薯6号、青薯9号以及具有推广潜力的2个新品种滇薯47、滇薯23为试验材料,采用超高效液相色谱-串联三重四级杆质谱仪(UHPLC-MS/MS),测定了不同时期块茎、茎、叶的α-卡茄碱、α-茄碱含量。结果表明:茎、叶中糖苷生物碱含量均随着生长进程的推进逐渐增高,在收获时达到最高,滇薯47收获期茎、叶总糖苷生物碱(Steroidal glycoalkaloids,SGAs)含量达256.84和427.25 mg/100 g·FW,显著高于其他三个品种(P<0.05)。而马铃薯块茎累积规律与茎、叶相反,随着块茎的成熟,块茎表皮、皮层和髓部α-卡茄碱、α-茄碱、总SGAs含量逐渐降低,并且收获时可食用部分(皮层和髓部)含量均低于国际推荐标准20 mg/100 g·FW,在安全食用范围内。综上,四个不同品种马铃薯块茎中糖苷生物碱含量随着马铃薯成熟逐渐降低;茎、叶中糖苷生物碱含量随着马铃薯成熟逐渐升高。滇薯47收获期茎、叶总糖苷生物碱含量显著(P<0.05)高于其他三个品种,可作为提取糖苷生物碱进行综合利用的备选品种。     

不同品种彩色马铃薯总花色苷含量与总抗氧化活性

以10 个彩色马铃薯品种为实验材料,采用pH示差法测量其总花色苷含量、1,1-二苯基-2-三硝基苯肼（2, 2-diphenyl-1-picrylhydrazyl,DPPH）法分析其总抗氧化活性,比较不同品种的彩色马铃薯的总花色苷含量和总抗氧化活性。结果表明：不同品种的彩色马铃薯的表皮、薯肉、整薯总花色苷含量的变化范围分别为59.67～293.57 mg/100 g、0～56.11 mg/100 g、1.34～63.32 mg/100 g;表皮、薯肉、整薯抗坏血酸当量（ascorbic acidequivalent antioxidant capacity,AEAC）的变化范围分别为2.74～6.43 mg/g、0.50～1.39 mg/g、0.65～1.50 mg/g。其中,紫云1号的总花色苷含量和总抗氧化活性均为最高;S05-603的总花色苷含量最低;S03-2677的总抗氧化活性最低。此外,整薯总花色苷含量与总抗氧化活性的正相关性极显著（P＜0.01）。     

Glycoalkaloid Concentrations in Aerial Tubers of Potato ( Solanum tuberosumL)

The total glycoalkaloid concentrations in aerial and subterranean tubers of 14 potato genotypes were measured using high-performance liquid chromatography immediately after harvest. Post-harvest, aerial tubers from all genotypes were exposed to 144 h continuous fluorescent light; additionally three genotypes (cvs Home Guard, Kerrs Pink and Desiree) were subjected to mechanical wounding prior to glycoalkaloid analysis. Variations in glycoalkaloid concentrations between aerial tubers taken from a single genotype (cv Kerrs Pink) were determined by analysis of eight aerial tubers formed in the second leaf axil, selected from separate individual plants. Irrespective of genotype, total and individual glycoalkaloid concentrations were higher in aerial than in subterranean tubers. The highest glycoalkaloid concentrations were found in aerial tubers of cv Kerrs Pink (1343·0 mg kg⁻¹ FW) and lowest in cv Lindsey (301·0 mg kg⁻¹ FW). Ratios of α-chaconine: α-solanine in aerial tubers differed significantly ( P< 0·05) from those in subterranean tubers of cv Cara, Golden Wonder, Home Guard, Lindsey, Maris Piper, Record and 8859 indicating that exposure to light during aerial tuber growth enhanced the synthesis of one glycoalkaloid to a greater degree than the other. In all cultivars except cv Maris Piper, exposure of aerial tubers to 144 h continuous fluorescent light post-harvest increased total and individual glycoalkaloids compared with dark-treated controls. However, the ratios of α-chaconine: α-solanine in all genotypes except cv Golden Wonder (decreased α-chaconine: α-solanine, P< 0·05) were not significantly altered in comparison with dark controls, indicating that light exposure of aerial tubers post-harvest fails to enhance selectively synthesis of individual glycoalkaloids in the majority of cultivars. Regardless of cultivar, total glycoalkaloid, α-solanine and α-chaconine concentrations were higher in wounded than unwounded aerial tubers. Wounding stimulated synthesis of α-solanine more than α-chaconine ( P< 0·05) in cv Home Guard and Desiree. Glycoalkaloid concentrations in aerial tubers varied widely from a minimum of 1010 mg kg⁻¹ to a maximum of 2520 mg kg⁻¹ FW when harvested from individual plants of cv Kerrs Pink but selected from equivalent positions on the plant. Throughout the experiments large, non-significant increases in total and individual glycoalkaloid concentrations were recorded following light and wounding treatments. The scientific implications of aerial tuber formation are discussed.     

Potato Glycoalkaloids: occurrence,biological activities and extraction for biovalorisation – a review

Potato tuber (Solanum tuberosum L.) is the fourth most important agricultural product after wheat, rice and maize. With a total production of 388 million in 2017, c.a. 70% of this total production is processed in developed countries, producing a large amount of potato peel waste (PPW) as by-product. Although PPW is considered as a zero-value by-product by the feed industry because it is too fibrous, for other recycling industries it is an inexpensive by-product due to its significant contents of some interesting nutrients particularly polyphenols and glycoalkaloids. In potato, and Solanum species in general, many glycoalkaloids, predominantly α-chaconine and α-solanine, have been chemically and structurally identified. However, further research is needed to expand the knowledge of the biological values of potato glycoalkaloids in order to develop a recycling process to extract these technologically and nutritionally interesting bioactive ingredients for different sectors, in particular, the agricultural, food and pharmaceutical ones, which are demanding natural, safe and eco-friendly ingredients.     

High levels of glycoalkaloids in the established swedish potato variety magnum bonum

In 1986, potentially toxic levels of the glycoalkaloids α-solanine and α-chaconine were unexpectedly found in tubers of the established Swedish consumer potato variety Magnum Bonum, leading to the imposition of a conditional sales ban on such potatoes. The combined amounts of α-solanine and α-chaconine in more than 300 commercial lots of Magnum Bonum potatoes analysed as a consequence of the ban ranged from 61 to 665 mg kg^?1 fresh weight with an average of 254 mg kg^?1. Sixty-six percent of the samples exceeded a temporary maximum residue limit of 200 mg kg^?1, 8% were above 400 mg kg^?1. Peeling did not significantly remove the glycoalkaloids in tubers with a high content. The occasional glycoalkaloid elevation was initially attributed to the unusually cold and rainy conditions during the late part of the season in 1986, but subsequent investigations have failed to confirm this hypothesis. Varietal characteristics are likely to have been involved since most other common Swedish varieties seemed to have had normal glycoalkaloid levels in 1986. There were no indications of serious or widespread adverse health effects in consumers due to the high glycoalkaloid levels, although there was circumstantial evidence that a few cases of temporary gastrointestinal disturbances were caused by consumption of Magnum Bonum potatoes with glycoalkaloid concentrations in the range 310–1000 mg kg^?1.     

Genetic and environmental effects on levels of glycoalkaloids in cultivars of potato (Solanum tuberosum L.)

Glycoalkaloids were assayed in fifty-five potato cultivars, fifty-four breeding lines and one other species (S. stolonifer). The total glycoalkaloid content ranged from 16·3 μg/g FW for Alpha to 317·0 μg/g FW for Berita, with most values lying between 35 and 65 μg/g. The α-solanine content, as a percentage of total glycoalkaloids, ranged from 28·3% for Avenir to 57·0% for H42, with the majority of values lying between 38% and 46% α-solanine. There was a highly significant correlation between high total glycoalkaloid content and per cent α-solanine (P < 1%). The presence of β₂-chaconine was also related in a highly significant way to high total glycoalkaloid content. Potatoes grown at Yanco (hot, dry, inland climate) contained more glycoalkaloids (～60%) than when grown at Glen Innes (cooler, high altitude climate). However, there was no significant difference between total and relative glycoalkaloid levels of cultivars grown at Glen Innes and Healesville (coastal, temperate climate). A significantly higher per cent α-solanine content, but not total glycoalkaloid content, was observed for potatoes grown in the second year at Glen Innes.     

高效液相色谱-串联质谱法测定茄科蔬菜及其制品中α-茄碱和α-卡茄碱的含量

目的建立通过式固相萃取-高效液相色谱-串联质谱法同时测定茄科蔬菜及其制品中α-茄碱和α-卡茄碱含量的分析方法。方法样品采用1%甲酸水溶液:乙腈=1:1 (V:V)涡旋提取, Oasis? PRiME HLB固相萃取(solid phase extraction, SPE)柱净化,经过色谱柱BEH Amide (2.1 mm×100 mm, 1.7μm)分离,以2 mmol/L乙酸铵的0.1%甲酸水溶液(A):2mmol/L乙酸铵的乙腈溶液(B)为流动相进行梯度洗脱,柱温40℃,流速0.4 mL/min,多反应模式监测,基质匹配标准曲线外标法定量。结果在1~500 ng/mL范围内,α-茄碱和α-卡茄碱与峰面积线性关系良好(相关系数r2>0.998)。在低、中、高3个水平添加下,α-茄碱回收率为91.3%~104.6%,α-卡茄碱回收率为90.3%~108.4%,相对标准偏差不超过5.5%(n=6)。结论该方法快速简便、准确度好、灵敏度高,适用于大批量茄科蔬菜及其制品中α-茄碱和α-卡茄碱的快速测定。     

UV-C处理抑制马铃薯贮藏期发芽及相关机理研究

为提高马铃薯的食用安全性和贮藏品质,本实验研究了短波紫外线(ultraviolet C,UV-C)处理对马铃薯贮藏过程中发芽品质的影响。采用10 kJ/m2 UV-C对马铃薯进行一次处理(贮藏前),二次处理(贮藏前及中期),并测定发芽率、还原糖、苯丙氨酸解氨酶、多酚、赤霉素、α-茄碱等指标。结果表明,UV-C处理能够有效抑制马铃薯贮藏过程中的发芽,同时延缓赤霉素和α-茄碱的上升。二次处理组贮藏至90 d时,薯皮和肉质部分的α-茄碱含量仅为对照组的71.09%、65.75%;105 d时发芽率为68.78%,还原糖含量为0.40%,失重率为4.71%,贮藏品质均优于对照组和一次处理组。综上所述,当处理剂量和方式适宜时,UV-C可在马铃薯发芽控制及品质保持方面获得良好效果,其中二次处理更具优势。     

Phenolic content and antioxidant activities of selected potato varieties and their processing by-products

The total content of free, esterified and bound phenolics of the peel and flesh of four potato varieties (Purple, Innovator, Russet and Yellow) were determined using the Folin–Ciocalteu method. The respective antioxidant activities of these potatoes and/or their skins were evaluated using several in vitro assays. The phenolic profiles of potato peel and flesh samples were determined using high-performance liquid chromatography with photodiode array detection (HPLC-DAD). Bound and esterified phenolics contributed as much or even more than the free phenolics to the antioxidant activity of the peels; extracts from Purple variety showing the highest activity. The peels of all varieties showed significantly (p < 0.05) higher phenolic content and antioxidant activities than their respective flesh. Chromatographic data showed differences in the amounts, but not in types, of phenolic compounds in the potato peel samples. Thus, potato processing discard may be used in food formulations and their extracts could potentially be employed as an effective source of antioxidants in food systems.     

Liquid Chromatography–Hybrid Linear Ion Trap–High-Resolution Mass Spectrometry (LTQ-Orbitrap) Method for the Determination of Glycoalkaloids and Their Aglycons in Potato Samples

Potatoes produce biologically active secondary metabolites like glycoalkaloids and their aglycons, which may have both adverse and beneficial effects in the diet. A new analytical method that uses liquid chromatography–mass spectrometry (LTQ-Orbitrap) has been developed for the analysis of glycoalkaloids and their aglycons in potato samples. Two glycoalkaloids, α-solanine and α-chaconine, and two aglycons, demissidine and solasodine, were quantified in potato samples. Samples were extracted using methanol, purified on an SPE Strata C₁₈ cartridge, and then analyzed in HPLC–mass spectrometry (LTQ-Orbitrap) with the FTMS operating in full scan at a resolving power of 30,000 (FWHM), enabling the detection and accurate mass measurement and with the ITMS mode operating in MRM (multiple reaction monitoring) for glycoalkaloids and their aglycons using the [M + H]⁺ ions and their optimized collision energies. After validation, the method was applied to screen different type of potatoes, and some cooking experiment were conducted.     

Sterol Content of Fish,Crustacea and Mollusc: Effects of Cooking Methods

Sterol contents (desmosterol, cholesterol, stigmasterol, and sitosterol) of 36 fresh and cooked seafood and four freshwater fish species were investigated by high performance liquid chromatography (HPLC) method. Cholesterol and sitosterol were main sterols in seafood and freshwater fish species. Raw shellfish and molluscs contained cholesterol above 18.92 mg/100 g fish muscle, while the cholesterol content of marine fish ranged from 6.5 to 78.40 mg/100 g fish muscle. The cooking process resulted in significant effects on the sterol contents of seafood and freshwater species (p < 0.05). A remarkable increase in sitosterol (more than 3–4 fold compared to raw fish) was recorded for some fish species cooked in the oven. The highest desmosterol content was observed for fried fish, whereas the frying process resulted in a significant loss in cholesterol and sitosterol contents of marine fish (p < 0.05). The impacts of cooking methods on sterol content of seafood and their form varied depending on fish species and the cooking method used.     

Daidzein and genestein contents in tempeh and selected soy products

The total isoflavones in tempeh and selected local soy products was determined. Raw tempeh contained 26 ± 6 mg daidzein (Da) and 28 ± 11 mg genestein (Ge) while fried tempeh contained 35 ± 11 mg Da and 31 ± 11 mg Ge in 100 g (wet basis). Total isoflavone content in 100 g of raw tempeh, based on a dry weight, was 205 ± 56 mg and significantly reduced to 113 ± 41 mg in 100 g of fried tempeh. Tempeh in batter was deep-fried for 30 min which reduced 45% of the total isoflavone content compared to the raw one. Raw tempeh contained the highest total content of isoflavone among the studied local soy products. Total isoflavone content in processed soy foods like egg tofu and home made soybean drink were significantly lower than other soy products studied.     

The effect of ultrasound-vacuum-assisted extraction on bioactive properties of pitaya (Hylocereus undatus)

This study aimed to investigate the effect of ultrasound-assisted extraction under vacuum on bioactive properties of peel and flesh of pitaya fruit, and also compare with sonication under atmosphere condition using the principal component analysis (PCA). Vacuum sonication exhibited better results for total phenolic (56.78–71.54 mg GAE per 100 g for peel; 11.03–17.92 mg GAE per 100 g for flesh) and total flavonoid (95.33–115.71 mg QE per 100 g for peel; 13.26–19.36 mg QE per 100 g for flesh) amounts. DPPH free radical scavenging activity values of peel and flesh increased from 1.97 to 2.53 mmol TE kg^-1; from 0.33 to 0.50 mmol TE kg^-1 after sonication process, respectively. The main phenolic compounds of pitaya were identified as catechin (1.15–20.31 mg per 100 g) and rutin (0.88–14.55 mg per 100 g) in peel; catechin (1.11–9.35 mg per 100 g) and 3,4-dihydroxybenzoic acid (1.29–3.60 mg per 100 g) in flesh. The combination of vacuum and ultrasound process can be used as a green extraction technology in order to enhance the amounts of bioactive compounds of pitaya fruit.     

Toxic and antifeedant activities of potato glycoalkaloids against Trogoderma granarium (Coleoptera: Dermestidae)

The total glycoalkaloid fraction (TGA) and the two glycoalkaloids, α-chaconine and α-solanine of potato, Solanum tuberosum, were isolated. Their toxic and antifeedant activities against the Khapra beetle, Trogoderma granarium Everts were investigated. Results indicated considerable toxicity, especially when adults were topically treated with the glycoalkaloids. The TGA fraction was the most toxic with LC₅₀’s of 16.7 and 11.9 μg/mg insect, 48 and 96 h post treatment, respectively. LC₅₀’s of α-chaconine and α-solanine 96 h post treatment were 18.1 and 22.5 μg/mg insect, respectively. Moderate toxicities were recorded when insects were confined on dry-film residues of botanicals with LC₅₀’s ranging between 26.1 and 56.6, and 19.4 and 45.7, μg/cm² 48 and 96 h post treatment, respectively. Nutritional studies using the flour disc bioassay revealed significant reduction in the growth rate (RGR), food consumption rate (RCR) and food utilization (ECI) by T. granarium at concentrations ranging between 20 and 30 mg g⁻¹ food with feeding deterrent indices reaching 82.4% with the TGA fraction. When tested as binary or crude alkaloidal mixtures, toxic and antifeedant activities of glycoalkaloids were increased, indicating some additive interaction among these botanicals. There is potential for use of such compounds to protect stored grains from insect infestation.     

Determination of acrylamide content of food products in Korea

Acrylamide (AA) contents of commercial market‐purchased foods and of traditional home‐cooked Korean foods were investigated. The effect of cooking method on AA amount in potatoes was also studied. AA contents of roasted barley and corn ranged from 116 to 449 µg kg^?1 and of chips ranged from 12 to 3241 µg kg^?1, representing a very high variation in AA contents among tested samples. Lower levels of AA were found in wheat flour chips compared to potato chips. AA contents of ramen noodles were below 37 µg kg^?1, whether they contained potato starch or not. The AA contents of Korean home‐cooked oil fried foods increased in the following order: yakwa < whole deep‐fried sea tangle < ground and deep‐fried lotus root < ground and pan‐fried lotus root < French fries < ground and pan‐fried potato. Lotus root and garlic also had the potential to produce AA during cooking. Pre‐treatment such as grinding, boiling, freezing and thawing increased the AA formation in oil‐fried potato. Temperature was more influential than time on AA formation during deep‐oil frying. Removing water‐soluble fractions reduced AA content of cooked potatoes. Copyright © 2006 Society of Chemical Industry