Effect of cultivar and storage time on the volatile flavor components of baked potato

Tubers of five cultivars of potato were stored at 4 degreesC for 2 3 and 8 months and baked in a conventional oven The flavor compounds from the baked potato flesh were isolated by headspace adsorption onto Tenax and analyzed by gas chromatography-mass spectrometry On a quantitative basis compounds derived from lipid and Maillard reaction/sugar degradation dominated the flavor isolates with sulfur compounds, methoxypyrazines, and terpenes making smaller contributions Levels of 37 of the > 150 detected compounds were monitored in each cultivar with time of storage Many significant differences were found in levels of individual compounds compound classes and total monitored compounds for the individual effects of cultivar and storage time and for their two way interaction Differences may be explained by variations in levels of flavor precursors and activities of enzymes mediating flavor compound formation among cultivars and storage times In addition differences in agronomic conditions may partly account for variations among cultivars Overall of the compounds monitored those most likely having the greatest flavor impact were 2-isopropyl 3 methyoxypyrazine 2 isobutyl 3-methoxypyrazine dimethyl trisulfide, decanal and 3 methylbutanal, with methylpropanal, 2 methylbutanal methional, and nonanal also being probable important contributors to flavor.

Comparison of the volatile components of two cultivars of potato cooked by boiling, conventional baking and microwave baking

Tubers of two cultivars (Estima and Maris Piper) of potato were cooked by three different procedures, ie boiling, conventional baking and microwave baking. Peeled and sliced tubers were boiled, while intact potatoes were baked in their skins. Flavour components from the boiled slices and the flesh of the baked tubers were isolated by headspace adsorption onto Tenax and analysed by gas chromatography-mass spectrometry (GC-MS). For all cooking procedures, Estima gave stronger isolates than Maris Piper. The two main sources of flavour compounds (regardless of cooking procedure) were lipid degradation and the Maillard reaction and/or sugar degradation. The ratio (yield derived from lipid)/(yield derived from Maillard reaction and/or sugar) decreased from 8.5-9.1 (boiling) to 2.7-3.4 (microwave baking) and to 0.4-1.1 (conventional baking). Quantitative and qualitative differences among the cooking procedures are explained in terms of the variations in heat and mass transfer processes that occurred. Each cooking procedure resulted in a unique profile of flavour compounds. (C) 2002 Society of Chemical Industry.

Comparison of the volatile components of eight cultivars of potato after microwave baking

Eight cultivars of potato were baked in a microwave oven. The flavour components of the flesh were isolated by headspace trapping onto Tenax and analysed by gas chromatography-mass spectrometry. Lipid degradation and the Maillard reaction and/or sugar degradation were the main sources of the 80 flavour components identified. It is suggested that total levels of compounds and variations among their profiles may be attributed to differences in activities of lipid enzymes and levels of flavour precursors in the range of cultivars investigated. (C) 2002 Elsevier Science Ltd.

Volatile flavour components of baked potato flesh. A comparison of eleven potato cultivars

Tubers of eleven cultivars of potato were baked and the flavour compounds from the flesh were isolated by headspace adsorption onto Tenax and analysed by gas chromatography-mass spectrometry (GC-MS). Lipid degradation and the Maillard reaction were the main sources of flavour compounds, accounting for 22-69% and 28-77%, respectively, of the total yields. Various sulfur compounds, methoxypyrazines and terpenes were also identified at lower levels. Relative aroma impact values (RAVs) were calculated by dividing compound yields by the odour threshold value. Compounds contributing most to aroma (RAV > 10000 in at least one cultivar) were 2-isobutyl-3-methoxypyrazine, 2-isopropyl-3-methoxypyrazine, beta -damascenone, dimethyl trisulfide, decanal and 3-methylbutanal. The observed differences in yields and RAVs for compounds among cultivars would be expected to result in differences in perceived flavour.

Choice and use of standards for dynamic headspace trapping and application to the analysis of the volatiles of baked potato

When attempting to quantify the volatile components of a food isolated by dynamic headspace trapping onto an adsorbent, the analyst has to select the most appropriate compounds to use as standards and at which stage of the analysis to add them. Factors to be borne in mind include the volatility of the standard, the response of the GC detector, and whether to add the standard to the sample or to the adsorbent trap. This chapter considers the issues and describes the application of one chosen method to the quantitation of the volatile components of baked potato.

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.

Formation of Strecker aldehydes and pyrazines in a fried potato model system

Sugars and amino acids were removed from potato slices by soaking in water and ethanol. They were then infused with various combinations of sugars (glucose and/or fructose) and amino acids (asparagine, glutamine, leucine, isoleucine, phenylalanine, and/or methionine) and fried. Volatile compounds were trapped onto Tenax prior to gas chromatography-mass spectrometry. Relative amounts of compounds (relative to the internal standard) and relative yields (per mole of amino acid infused into the slices) were determined. Amounts of 10 pyrazines, 4 Strecker aldehydes, and 4 other compounds were monitored. Relative amounts and relative yields of compounds varied according to the composition of the system. For the single amino acid-glucose systems, leucine gave the highest relative amount and relative yield of its Strecker aldehyde. Asparagine and phenylalanine gave the highest total relative amount and total relative Yield, respectively, of pyrazines. In the system containing all of the amino acids and glucose, the relative amount of 3-methylbutanal was higher, whereas the amounts of the other monitored Strecker aldehydes were lower. Most of the relative amounts of individual pyrazines were lower compared to the glucose-asparagine system, whereas the total relative yield of pyrazines was lower, compared to all of the single amino acid-glucose mixtures. Addition of fructose to the mixed amino acid-glucose model system generated Strecker aldehydes and pyrazines in ratios that were more similar to those of untreated potato chips than to those from the same system but without fructose. Both the sugars and the amino acids present in potato are crucial to the development of flavor compounds in fried potato slices.