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.     

不同颜色PE 食品包装袋对马铃薯绿化和龙葵素含量的影响

研究不同颜色包装袋对马铃薯绿化和龙葵素含量的影响。结果表明：在自然光照条件下,马铃薯表皮绿化速度和程度以及龙葵素含量随贮藏时间延长而迅速增加;不同颜色包装袋包装可有效控制马铃薯绿化及龙葵素含量的增加,其中绿色和黑色包装袋对其控制效果较优,马铃薯贮藏45d,黑色和绿色包装袋包装的马铃薯叶绿素含量比对照分别降低53.97% 和65.89%,龙葵素含量分别降低80.71% 和75.89%。     

An enzyme-linked immunosorbent assay for total glycoalkaloids in potato tubers

An antiserum raised against a solanine-bovine serum albumin conjugate has been characterised and shown to be specific for the glycoalkaloids found in commercially available potatoes. The antiserum has been employed at high dilution in an enzyme-linked immunosorbent assay (ELISA) for the glycoalkaloids. The assay is sensitive and precise and has many advantages over alternative procedures currently employed. Potato sample preparation is minimal and no recovery factors are required.     

Changes in glycoalkaloid and nitrate contents in potatoes during French fries processing

The purpose of this investigation was to determine the influence of various stages of French fries processing on the contents of glycoalkaloids and nitrates in potatoes. The material for the study comprised samples of two potato varieties, Santana and Innowator, collected from nine stages of a French fries production line. Based on the results of the research carried out, it was found that the processes applied during French fries production had a significant influence on the decrease in glycoalkaloid (chaconine and solanine) and nitrate contents in both intermediate products and the final product in comparison with the raw material. The highest amounts of glycoalkaloids and nitrates were removed during peeling, blanching and frying. In the processed potatoes the ratio of chaconine to solanine decreased. French fries ready for consumption contained only 3–8% of the glycoalkaloids and 5–6% of the nitrates found in the raw material. Copyright © 2004 Society of Chemical Industry     

The influence of washing and selection processes on the contents of glycoalkaloid and other toxic compounds during industrial chip production

The aim of this study was to determine the influence of pretreatment selection and washing processes of potatoes on the manual and optic control on the contents of nitrates (V), and glycoalkaloids after the peeling and frying processes are applied in the industrial production of potato chips. The highest reduction in nitrate quantity was found after the manual selection process of the potatoes and their slicing, as well as after frying the chips. The preselection process of the raw material, slicing and rinsing the potato slices, as well as frying the chips, had the largest influence on the losses of glycoalkaloids. In these samples, 74% remained after pretreatment of the raw material, 29% remained after slicing, and 10% remained in the chips after frying relative to the unpeeled potatoes.     

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.     

马铃薯中龙葵碱的研究进展

龙葵碱是马铃薯中产生的一类天然次生代谢产物，马铃薯一旦发芽、变绿、发霉、腐烂或受到机械伤害时，就会引起其块茎自身合成较高含量的龙葵碱，食用含龙葵碱超过200 mg/kg（FW）的马铃薯就会引起人的中毒反应。马铃薯作为日常餐桌上常见的食物，其安全性尤其重要，关乎着老百姓们的健康问题。本文通过国内外最新的研究资料，对龙葵碱种类及结构、提取及检测方法、生物合成途径几个方面进行了概述。而对于龙葵碱生物合成方面的研究，更是今后研究的重点，为今后在基因水平上调控龙葵碱的合成打下基础。本文介绍了最新的龙葵碱生物合成途径，即从乙酰辅酶A到胆固醇、从胆固醇到甾体类生物碱及甾体类生物碱的糖基化过程。掌握马铃薯龙葵碱的最新的研究态势，对研究马铃薯龙葵碱及马铃薯块茎及其制品的食用安全性具有重要意义。     

Survey of glycoalkaloids content in the various potatoes

The content of potato glycoalkaloid (PGA) was investigated in 27 cultivars of raw potatoes and 31 potatoes in commercial foods with peel. The investigation of the 27 cultivars of potatoes showed different contents of glycoalkaloids. "May queen" and "Sherry" showed high contents of PGA (180 mg/kg and 320 mg/kg, respectively) among the raw potatoes of middle size (ca. 100 g). On the other hand, "Inca red" showed the lowest content of 21 mg/kg. Higher contents of PGA were found in smaller potatoes in this study. The content of PGA varied in the range of 48-350 mg/kg in the potatoes in commercial foods with peel.     

Safety assessment of genetically engineered potatoes with designed soybean glycinin: compositional analyses of the potato tubers and digestibility of the newly expressed protein in transgenic potatoes

The compositions of transgenic potatoes with intact and modified genes for soybean glycinin were compared with those of control potatoes; non-transgenic or transgenic ones with a vector. The expression levels of glycinin proteins in the transgenic potato tubers were approximately 12–31 mg g⁻¹-total soluble protein. With reference to six major components, moisture, protein, lipid, fiber, ash and carbohydrate, there were no significant differences between transgenic and control potatoes. The levels of glycoalkaloids in transgenic potato tubers, as well as in transgenic controls, increased in comparison with those in non-transgenic ones, though the level was within the permitted limit. The modified glycinin expressed in the transgenic potato tuber was digested under the simulated gastric conditions. From these results, the transgenic potatoes with intact and modified glycinin genes are considered to be as safety utilization for food as non-transgenic potatoes. © 1999 Society of Chemical Industry     

Investigation of the contents of phenolic and alkaloidal compounds of gamma irradiated potatoes during storage

The contents of phenolic cinnamic acids and coumarins as well as of the glycoalkaloids of gamma irradiated potato tubers have been studied in detail. Gamma irradiation up to 3 k Gy had no effect on the glycoalkaloid contents of two potato tuber varieties during a four months storage period. The phenolic compounds behave differently and show a considerable change during storage in potatoes irradiated at the highest dose level, 3 k Gy. A time dependent change of phenolic extracts was observed. This change of phenolic compounds could be partly ascribed to the β-glycoside of scopoletin (coumarin, 7-hydroxy-6-methoxy) and was accompanied by a general decrease of chlorogenic acid, the main hydroxy-cinnamic acid of potatoes.     

Health‐beneficial properties of potato and compounds of interest

Potatoes have shown promising health‐promoting properties in human cell culture, experimental animal and human clinical studies, including antioxidant, hypocholesterolemic, anti‐inflammatory, antiobesity, anticancer and antidiabetic effects. Compounds present such as phenolics, fiber, starch and proteins as well as compounds considered antinutritional such as glycoalkaloids, lectins and proteinase inhibitors are believed to contribute to the health benefits of potatoes. However, epidemiological studies exploring the role of potatoes in human health have been inconclusive. Some studies support a protective effect of potato consumption in weight management and diabetes, while other studies demonstrate no effect and a few suggest a negative effect. As there are many biological activities attributed to the compounds present in potato, some of which could be beneficial or detrimental depending on specific circumstances, a long‐term study investigating the association between potato consumption and diabetes, obesity, cardiovascular disease and cancer while controlling for fat intake is needed. © 2016 Society of Chemical Industry     

Zur Bestimmung der Solanum-Alkaloide Solanin und Chaconin

Zusammenfassung Es wurde eine quantitative Bestimmungsmethode für Solanin und Chaconin in den Knollen, Keimen und Blattern vonsolanum tuberosum entwickelt, die a) einer schonenden Aufarbeitung des Glykosidgemisches aus dem Kartoffelmaterial durch Extraktion mit Pyridin Rechnung trägt und b) eine quantitative Bestimmung des Glykosidgemisches gaschromatographisch durch Derivatisierung mit Trimethylsilyl-Donoren ermöglicht.

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On the determination of the solanum alkaloids solanine and chaconine

Summary A new analytical method for quantitative determination of solanine and chaconine in potato tubers, sprouts and leaves has been developed: a) The extraction with pyridine causes a careful isolation of glycoalkaloids; b) the glycoalkaloids are determined by gaschromatography after silylation.

     

Quality of organically and conventionally grown potatoes: Four-year study of micronutrients, metals, secondary metabolites, enzymic browning and organoleptic properties

The quality of potatoes from organic and conventional farming was investigated in this study. Tubers of eight potato varieties, organically and conventionally produced at one or two geographical sites in controlled field trials, were collected in four consecutive harvests from 1996-1999. The parameters analysed included nitrate, trace elements (As, Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn), vitamin C, potato glycoalkaloids, as well as chlorogenic acid, polyphenol oxidase and rate of tuber enzymic browning. The results indicated lower nitrate content and higher vitamin C and chlorogenic acid content to be the parameters most consistently differentiating organically from conventionally produced potatoes. Elevated concentrations of glycoalkaloids were also observed throughout the experiments in some potato varieties grown in organic farming systems. Principal component analysis (PCA) of the analytical and other data using three PCs confirmed a good separation between the organically and conventionally produced potatoes when studied in single crop years. However, score-plots (objects) and loading-plots (variables) of pooled results from the consecutive harvests showed that between the years' changes and also variety as well as geographical variations are equally or more important factors determining the quality of potatoes than the farming system. Further studies of various marker compounds of potato quality related to the organic or conventional farming systems should be performed before unbiased information can be given to the consumers.     

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).     

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.     

Effect of Packaging Materials on the Chemical Composition of Potatoes

Russet Burbank and Chieftain potatoes were packaged in either mesh, paper or polyethylene bags and compared in chemical composition after 1, 4, and 8 wk of storage at 20^oC. Potatoes were analyzed for weight loss, discoloration, phenols, ascorbic acid, glycoalkaloids and nitrate-nitrogen. Potatoes packaged in polyethylene were lowest in weight loss, ascorbic acid and nitrate-nitrogen and highest in discoloration, phenols and glycoalkaloids than those packaged in mesh or paper. Potatoes packaged in paper were lowest in discoloration and phenols and highest in ascorbic acid. There were no significant differences in weight loss, glycoalkaloids or nitrate-nitrogen between potatoes packaged in mesh on paper.     

Effect of Peeling on Total Phenols, Total Glycoalkaloids, Discoloration and Flavor of Cooked Potatoes

The effect of peeling on the total phenols, total glycoalkaloids (TGA), discoloration, and flavor of 50–80g sized cooked potatoes was studied. Three methods of cooking were studied; (1) boiling in distilled water; (2) boiling in 16% NaCl solution; and (3) steaming. In all three methods, potatoes cooked without the peel were lower in phenolic and TGA content, discolored less, and were less bitter than potatoes cooked with the peel. During cooking phenols migrated from the peel into both the cortex and internal tissues of the potato. Glycoalkaloids were less mobile than phenols and migrated only into the cortex. The movement of phenols and TGA into the cortex increased both discoloration and bitterness in potatoes cooked with the peel.     

Content of anthocyanins and glycoalkaloids in blue‐fleshed potatoes and changes in the content of α‐solanine and α‐chaconine during manufacture of fried and dried products

In the last ten or so years, potatoes with purple or blue‐flesh and derivative products, for example chips, have appeared on the European markets. The interest in this raw material and these products is increasing among both producers and consumers searching for novel and attractive choices. The anthocyanin content of the analysed potato varieties differed; a higher content of these pigments was determined in Blaue Elise var. potatoes. In blue‐flesh varieties, the prevailing anthocyanins were acylated glycosides: petunidin and malvidin. The production process of French fries, chips and puree caused a decrease in the content of glycoalkaloids in semi‐products and finished products, compared to the raw material. The greatest losses of α‐chaconine and α‐solanine were observed after tuber peeling (ca. 70%) and after frying (ca. 90%). French fries contained 3%, chips 16% and puree 17% of the initial amount of total glycoalkaloids. The losses of α‐chaconine and α‐solanine in the analysed semi‐products and finished products were at the same level, regardless of the processing technology applied.     

Radiation preservation of foods of plant origin. Part 1. Potatoes and other tuber crops

In Part 1 of a planned series of articles on preservation of foods of plant origin by gamma irradiation, the current state of research on the technological, nutritional, and biochemical aspects of sprout inhibition of potatoes and other tuber crops are reviewed. These include varietal responses, dose effects, time of irradiation, pre‐ and postirradiation storage, and handling requirements; postirradiation changes in carbohydrates, ascorbic acid, amino acids, and other nutrients; respiration; biochemical mechanisms involved in sprout inhibition; wound healing and microbial infection during storage; formation of wound and light‐induced glycoalkaloids and identification of irradiated potatoes. The culinary and processing qualities with particular reference to darkening of boiled and processed potatoes are discussed. The prospects of irradiation on an industrial scale as an alternative to chemical sprout inhibitors or mechanical refrigeration are considered.     

Quantitative analysis of phenolic components and glycoalkaloids from 20 potato clones and in vitro evaluation of antioxidant,cholesterol uptake,and neuroprotective activities

Potato (Solanum tuberosum L.) is one of the most important food crops in the world and provides essential nutrients. With an aim to develop potato varieties for functional food or nutraceutial applications, we have conducted metabolomic profiling, total phenolics, chlorogenic acid, anthocyanins, and glycoalkaloids analyses on 20 selected potato clones within the Canadian potato breeding program of Agriculture and Agri-Food Canada. Pigmented potatoes in general contain higher levels of phenolic components, including chlorogenic acid and anthocyanins. Levels of phenolics were retained with granulation processing of pigmented potato tubers, but glycoalkaloids were significantly reduced with granulation. The pigmented potatoes also have higher antioxidant activity reaching up to 35% of that for berries, measured as their potency in scavenging DPPH radicals. Extracts of the 20 potato clones (peel, tuber, and granule) were also evaluated for in vitro effects on liver LDL cholesterol uptake and protection of cortical neurons from cell death caused by oxygen glucose deprivation (OGD). These potato extracts in general showed mild activity in enhancing LDL cholesterol uptake in liver HepG2 cells, and also protected cortical neurons against OGD induced cell death, with extracts from granules of six of the potato clones showing significant neuroprotective effects. The bioactive components are not dependent on pigmentation of potato clones. These novel bioactivities identified in potatoes warrant in-depth investigations in the future. Taken together, our results provide further evidence for the enhanced health beneficial components in potato.