Analysis of Free and Esterified Ergosterol in Tomato Products

Abstract

A new extraction and chromatographic procedure to quantify free and esterified ergosterol in tomato products was devised. The extraction solution was composed of a dichloromethane/methanol mixture in a 2:1 (v/v) ratio. This extraction solvent allowed for higher ergosterol recovery from tomato products (an average of 25% more) compared to hexane, which is frequently employed for ergosterol extraction. Both free and esterified ergosterol were determined by HPLC reverse-phase chromatography employing a Nova-Pak C-18 column (300 x 3.9 mm), filled with 4 mm average particle size and a guard column of the same material. The elution was performed at a flow rate of 1 mL. min(-1) with a linear gradient of solvent A (methanol/water, 80:20, v/v) and solvent B (dichloromethane). The gradient, starting at sample injection, was from 0 to 50% B for 20 min for the free ergosterol analysis and additional 15 min at 50% B to analyze the ergosterol esters. This technique has proven to be more sensitive for ergosterol determination than other reported chromatographic procedures. Moreover, ergosterol esters, extracted from various fungal sources, separated well and were easily quantified.

Resistance to Botrytis cinerea in Solanum lycopersicoides involves widespread transcriptional reprogramming

“…Ergosterol was then extracted from ground leaf tissue (150–550 mg) and analyzed by high pressure liquid chromatography as described by de Sio et al [104] with minor adjustments. Briefly, ground leaves were added to 2.0 ml of 2:1 chloroform:methanol and extracted overnight.…”

Identification and quantification of ergosterol and phenolic compounds occurring in Tuber spp. truffles

“…Ergosterol (5,7,22-ergostatrien-3b-ol), a type of plant sterol, is a topic of research because the content is usually associated with structural and growing fungal characteristics, such as the age, maturation, hyphal formation, and sporulation (Cheikh-Rouhou et al, 2008;de Sio et al, 2000). Ergosterol is present in two main forms, which are free and esterified, and the relative quantities would depend on the fungal species (Phillips et al, 2011).…”

Effects of Temperature and Packaging Types on Ergosterol and Howard Mold Count Values of Tomato Paste during Storage

“…Ergosterol is present in two forms, as free ergosterol and esterified ergosterol, and the relative abundances of free and esterified ergosterol are different among various species (7). However, because of the similarity between tomato tissue and cells with mold mycelium, it is quite difficult to determine the types and amount of molds in tomato products (2,10).…”

“…However, because of the similarity between tomato tissue and cells with mold mycelium, it is quite difficult to determine the types and amount of molds in tomato products (2,10). Fungal contamination of food, generally derived from poor manufacturing practices utilizing moldy plant material, is usually determined by microbial counting techniques, such as the Howard mold count (HMC) method (7). These methods are subjective and require special training and experienced microscopists.…”

“…Based on current analysis and knowledge, ergosterol has recently been recognized as a potential objective parameter useful for characterizing the quality of tomatoes for processing. Thus, a limiting value of 15 mg of total ergosterol per kg of total solids has been accepted as an index of acceptable quality for tomato products (3,5,7,8,20). However, the importance of ergosterol for quality control of tomatoes and tomato products has not been fully exploited.…”