Juice produced from the leaves of Justicia secunda is claimed to have potentials for treating anemia but is highly perishable while the production conditions are not yet mastered. Meanwhile in juice production from fruits or vegetables, key processing steps include extraction and pasteurization which are usually carried out separately with an attendant consequence on the production cost. This work was aimed at combining these unit operations in order serve time and energy. The effect of Conventional Extraction followed by Pasteurization (CEP) in comparison with Simultaneous Extraction and Pasteurization (SEPA) on the Vitamin C content of the juice was investigated. Kinetic models indicated that, the variation of Vitamin C occurred in two phases; a first phase corresponding to the accumulation of Vitamin C in the extraction medium and a second phase corresponding to its degradation. Average Vitamin C in the juice from the SEPA process was significantly greater than that from the CEP process. Major gains from the SEPA process include gain in energy, reduction in processing times and higher retention of Vitamin C in the juice.

Simultaneous extraction and pasteurization (SEPA) has recently been presented as an appealing process in juice processing because of significant reduction in time, energy consumptions, and production cost resulting from the combination of unit operations. However, the optimum SEPA operating conditions and their effects on the quality and shelf-life of juice are still unmastered. The Doehlert experimental design was used to optimize the SEPA process of juice from Justicia secunda leaves. Optimum conditions for vitamin C retention were temperature (80 C), quantity of ginger (2.6 g/100 ml) and time (20 min) which gave a vitamin C concentration of 4.61 mg/100 ml. The second part of the study evaluated the stability of juice using ginger powder as a natural stabilizer. Results showed that juice produced with and without ginger (WOG) retained 81.27 and 51.18% of their initial vitamin C contents on Day 9 of storage, respectively. Vitamin C content, pH, and acidity showed that addition of ginger preserved the quality of the juice better than that WOG throughout the storage period. Ginger is a natural source of preservative that contributes to the vitamin C content of the juice and extends its shelf-life from 3 to 9 days for storage at room temperature. Practical applications This work describes simple procedures that can be used to extract and pasteurize juice from plant material with simple equipment simultaneously. The optimum conditions that retain more than 90% of the initial vitamin C content of the juice are defined and the use of ginger as a natural preservative that prolongs the shelf-life of the drink at room temperature makes the process very appealing. The process can be easily adapted and used at both laboratory, local and industrial levels to produce juice of good quality. 1 | INTRODUCTION Today, the consumption of juice worldwide is on the rise because of the increasing believe that juices can introduce several nutrients to boost the overall health of an individual. This is because most vegetables and fruits; the major feedstocks for juice extraction are rich in vitamins and minerals. Juice can beef up the human immune system because of its anti-inflammatory properties (Onoja, Ezeja, Omeh, & Onwukwe, 2017). Extraction and pasteurization are some of the critical steps in juice process engineering because a carefully