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Ketchup flow properties were investigated with a concentric cylinder viscometer in the temperature range .from 30°C to 80°C. A partial characterization of the product viscoelastic behavior at 30°C was also made by "Strain test" and "Frequency test. " The Harper and El Sahrigi equation (7" = acJ eEdRT), as well as the equation that links the apparent viscosity of ketchups to the serum viscosity and to the pulp content (% = qserum +A(%PJB), do not describe adequately the ketchup flow behavior that we found to be highly affected by the production technology and by the raw materials used.

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.