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This work aimed to study the effect of ultrasound-assisted (UAE), microwave-assisted (MAE), and ultrasound-microwave-assisted (UMAE) methods for pectin extraction from industrial tomato waste. The overall performance index from the fuzzy analytical method with three criteria, pectin yield, galacturonic acid, and lycopene content, was applied to evaluate the best extraction conditions by using the weight of 75, 20, and 5, respectively. The UAE conditions was performed at a temperature of 80 °C for 20 min with the variations in the extraction pH and the solid liquid (SL) ratio. The best UAE conditions with high pectin yield, and high total carboxyl group, as well as a lycopene content, was the pH of 1.5 and the SL ratio of 1:30. The MAE conditions was performed with variations in the microwave powers and times. The results showed that the best MAE conditions were 300 W for 10 min, which gave high pectin yield with high galacturonic acid and lycopene content. Various conditions of UMAE at the best conditions of MAE and UAE were performed and exhibited that the UAE had more positively affected the pectin yield. However, the FTIR spectra of obtained pectins from different extraction techniques showed a similar pectin structure.

Pectin can be extracted from many fruits and also by-product from industry. Tomato can be produced into many products led to large amount of waste. This work aims to extract pectin from tomato waste achieved by tomato paste industry using Ultrasound Assisted Extraction (UAE) method (temperature of 40, 60 or 80 o C and time of 10, 15, 20 or 30 min, at pH of 2.5 and solid: liquid ratio of 1:40 w/v) using citric acid as an extractant. Moreover, the extractant (citric acid, hydrochloric acid and nitric acid) for pectin extraction under best UAE condition were compared, as well as physical and chemical properties of obtained pectin were determined. The results showed that the temperature of 80 o C and time of 20 min providing the highest pectin yield with shorter time. Moreover, the citric acid gave the highest yield compare to the other acid extractant. Citric acid extraction gave pectin with higher anhydrouronic acid content (31.59%), however, it gave comparable methoxyl content compare to others. Furthermore, citric acid extraction pectin could be categorized as low DM pectin while the others gave the high DM pectin. All obtained pectin were highly color and the a* of pectin extracted with citric acid was the lowest. Nevertheless, the extractant was not significantly impact to lycopene content (6.65-9.35 mg/100g pectin). This suggest that UAE method together with citric acid extraction could be used as an efficient method for pectin extraction with interestingly lycopene content.

The bioactive compound of tomato waste from industry was microwave-assisted extracted in different conditions including microwave powers of 180, 300 and 450 W and the extraction time of 30, 60 and 90 s. After extraction, the fractionation was performed to separate the hydrophobic fraction (hexane fraction) and hydrophilic fraction (ethanolic fraction). The bioactive compound and its DPPH radical scavenging activity were determined. For the hydrophobic part, the results showed that the microwave power of 300 W for 60 s gave the highest trans-lycopene and beta-carotene (5.74 mg lycopene/100 g and 4.83 mg beta-carotene/100 g) while the highest DPPH radical scavenging was the extracts at a microwave power of 180 W for 90 s. For hydrophilic parts, the best extraction condition giving the highest total phenolic compound (280.10 mg GAE/100 g) and total flavonoid content (9832.52 mg CE/100 g DM) were at 180 W for 90 s and 450 W for 30 s, respectively. However, the highest antioxidant activity was the extract of 300 W for 60 s. Fuzzy assessment analysis exhibited that the best condition was microwave power of 300 W for 60 s with high antioxidant activity of both fractions.

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