This study was conducted to evaluate the quality of sauces and ketchups by studying their physicochemical, microbiological properties, vitamin, traceelements, minerals, preservatives and heavy metals content. Five samples of each type of sauces and ketchups were collected for this experiment. Each value represents the average from five replications and the outcomes expressed as mean values ± standard deviations (SD). All the results were expressed as gram (g), percentage (%), kilocalorie (Kcal), milligram (mg) and microgram (μg) per 100 g of sauces and ketchups.
Sample collection This experiment was carried out at Institute of Food Science and Technology, BCSIR, Dhaka. Ten different types of sauces and ketchups from dissimilar producers were analyzed in this study. The selected sauces and ketchups were collected from different markets and superstores in Dhaka city. Collected samples were fresh, sealed and free from any kind of deterioration.
Sample preparation The sample was homogenized and accurate amount was weighed as required for different analysis. Five samples of each type of sauces and ketchups were selected for measurement.
Determination of physico-chemical properties The pH was determined with a digital pH meter and titratable acidity was estimated with the visual acidbase method (Ranganna, 1986). The moisture content was determined by the digital moisture analyzer. The total soluble solid (TSS) was determined with a hand refractometer (Jahan et al., 2011). Crude fiber, total fat was determined by the standard AOAC method (AOAC. 2005) and the estimation of total protein was made by the method (Kirk and Sawyer 1991). The content of total carbohydrate and energy was determined by the method (Osborn and Voogt, 1978).
Determination of vitamin-C and minerals Vitamin C was determined by the method of Bessey and King (Jahan et al., 2011). Ash was determined by the process (Ranganna, 1986). Sodium and potassium contents were determined by flame photometric method mentioned by Ward and Johnston (Jahan et al., 2011). Calcium, Magnesium, Copper, Iron, Manganese, Zinc and Chromium were determined by Flame Atomic Absorption Spectrometric method (Kirl and Sawyer, 1991).
Determination of preservatives Sulpher di-oxide was determined by titration process (Ranganna, 1986) and Sodium Benzoate was determined by the method (krik and Sawyer, 1991).
Determination of heavy metals Aluminum, Arsenic, Mercury, Lead, Tin and Cadmium were determined by Flame Atomic Absorption Spectrometric method (Kirk and Sawyer, 1991).
Bacterial analysis of collected samples For the quantitative determination of total count of mesophilic bacteria, total coliform, the standard procedure was followed (FDA, 2001). Aerobic plate count (APC) was performed by pour plate method using plate count agar (PCA), which was incubated at 35±100 C for 48±2h. Lauryl tryptose broth was used for isolation of Escherichia coli. Gassing tube was selected for E.coli enumeration using most probable number (MPN) method. Enumeration of fungi was performed on rose Bengal agar medium.
Statistical analysis Statistical analyses were carried out by using Statistical Package for Social Science (SPSS) for Windows version 15.0. The results obtained in the present study are reported as mean values (obtained from the five replications) ± standard deviation (SD). Mean values were analyzed using student T test. The significant differences between mean values were analyzed by the Duncan multiple range test at a significance level of p<0.05.