Effects of different stevia-to-onion ratios and heating temperatures on physicochemical and sensory attributes of onion-stevia hot water extracts

Abstract

Increased consumption of artificial and intense natural sweeteners have led to serious health implications and safety issues for intended consumers. Among all natural sweeteners, steviol glycosides (SGs: stevioside & rebaudioside-A) are popularly known as zero-caloric intense sweetening compounds of natural origin. Hot water extraction (HWE) is considered ecofriendly and less expensive, and HWE extracts are safe for human consumption as compared to organic solvents extraction. Onion (Allium cepa L.) and stevia (Stevia rebaudiana) were extracted using a single factor experimental approach to determine the optimal onion-stevia hot water extract (OSHE) extraction conditions. Physicochemical and sensory attributes of onion hot water extract (OHE) and OSHE extracted at varying stevia-to-onion ratios and temperatures were investigated. The results showed that total phenolic content (TPC) increased and total flavonoid content (TFC), L*, a* and b* values decreased with corresponding increases in stevia-to-onion ratio and extraction temperature. In contrast, total soluble solids increased with increase in onion-stevia ratio, whereas pH values declined with increasing temperature. Glucose was the most dominant organic sugar in OSHE followed by sucrose and fructose. In conclusion, OSHE obtained at 115 °C and 1:100 stevia-to-onion ratio (w/w) could be produced as a natural sweetener after concentration or drying and could be exploited in beverages and cooked foods without any deteriorating quality effects with improved thermal and pH stability and fermentation resistance. Furthermore, OSHE can be manufactured as a natural sweetener because it can be extracted at high temperature and pressure using stevia leaves with only the bound water content of onion without any additional moisture from external sources. As an eco-friendly alternative of expensive enzymatic digestion or organic solvent extraction.

Optimization of spray drying process for recovery of onion–stevia leaf hot water extract powder using response surface methodology

“…Based on our previous study, OSHE was prepared by the following process as per the reported method of Yang et al ( 2021 ). Onion and stevia (onion:stevia ratio = 100:1, w/w) were heated at 115°C, for 4 h, at a pressure of 1.2 kgf/cm 2 , using a retort (STERI‐ACE PRS‐60‐1, Kyunghan Co., Ltd, Gyeongsan, South Korea).…”

“…Onion comprises of moisture (ranging from 88.6% to 92.8%), fat trace (0.2%), ash (0.6%), and carbohydrates (ranging from 5.2% to 9.1%) (Bogevska et al, 2016 ; Griffiths et al, 2002 ; Jiang et al, 2021 ). The majority of the compositional framework of onion comprises dry matter content having nonstructural carbohydrates, such as fructans, sucrose, fructose, and glucose (Li et al, 2020 ; Yang et al, 2021 ). The sugar content of onion is subjected to variability during storage depending on storage temperature, postharvest treatments, and cultivar type.…”

Phytochemical profiling, antimicrobial, and antioxidant activities of hydroethanolic extracts of prickly pear (Opuntia ficus indica) fruit and pulp

“…These molecules are exacerbating factors in cellular injury and aging processes. In foods, ROS can cause lipid peroxidation, which leads to the deterioration of the foodstuffs (Li et al, 2020 ; Yang et al, 2021 ). The oxidative deterioration of lipid‐containing foods is responsible for the rancid odors and flavors during processing and storage, consequently decreasing the nutritional quality and safety of foods due to the formation of potentially toxic secondary compounds.…”