Dorothy Mokoena Z, Suinyuy Terence N, Lubaale John, Peter Bamidele O
School of Agricultural Science University of Mpumalanga Mbombela South Africa.
School of Environmental Science University of Mpumalanga Mbombela South Africa.
Food Sci Nutr. 2023 May 10;11(8):4607-4615. doi: 10.1002/fsn3.3423. eCollection 2023 Aug.
Marula fruit is one of the most underutilized fruits in South Africa, and it has been reported to contain a high amount of vitamin C which is regarded as the cheapest antioxidant. The fruit pulp is traditionally extracted and boiled into juice, a process that adversely affects the vitamin C and bioactive phenolic profile of the resulting juice. This study evaluated the effects of boiling and steaming on the physicochemical properties of marula fruit juice. The pH, percentage yield, total titratable acidity (TTA), total soluble solids (TSS), total phenolic content (TPC), radical scavenging capacity, and vitamin C content of the fruit juice were examined. The study also investigated the total carotene, color, and sensory properties of the fruit juice. The results showed that boiling and steaming significantly decreased the Vit C content of the juice (75.67 and 60.05 mg/100 g) compared to control sample (95.11 mg/100 g). The TPC, radical scavenging capacity, and total carotene content of the fruit juice increase because the heating processes softened the matrix of the fruit increasing the extractability of the phenolics and carotene content of the samples. The color of the marula fruit juice was increased by both boiling and steaming, while the sensory properties of the marula fruit juice extracted from steamed marula fruit had the highest scores in all the measured parameters. Steaming of marula fruit before juice extraction improved the nutritional composition, antioxidant activities, and sensory properties of marula fruit juice.
马鲁拉果是南非最未得到充分利用的水果之一，据报道其含有大量维生素C，而维生素C被视为最便宜的抗氧化剂。传统上，人们会将水果果肉提取出来并煮成汁，这一过程会对所得果汁的维生素C和生物活性酚类成分产生不利影响。本研究评估了煮沸和蒸煮对马鲁拉果汁理化性质的影响。检测了果汁的pH值、产率百分比、总可滴定酸度（TTA）、总可溶性固形物（TSS）、总酚含量（TPC）、自由基清除能力和维生素C含量。该研究还调查了果汁中的总胡萝卜素、颜色和感官特性。结果表明，与对照样品（95.11毫克/100克）相比，煮沸和蒸煮显著降低了果汁中的维生素C含量（分别为75.67和60.05毫克/100克）。果汁的TPC、自由基清除能力和总胡萝卜素含量增加，因为加热过程使水果基质软化，提高了样品中酚类和胡萝卜素的提取率。煮沸和蒸煮都增加了马鲁拉果汁的颜色，而从蒸煮过的马鲁拉果中提取的果汁在所有测量参数中的感官特性得分最高。在提取果汁之前对马鲁拉果进行蒸煮，改善了马鲁拉果汁的营养成分、抗氧化活性和感官特性。
