Evaluation of ohmic heating for sterilization of berry-like fruit juice of mulberry (Morus nigra), bignay (Antidesma bunius), and jambolana (Syzygium cumini)

Abstract

Increasing awareness on healthy lifestyles escalated the demand for health beneficial products which lead to the creation of minimally processed products using novel technologies. Ohmic heating considered as an emerging sterilization technology which adopt the principle of High-Temperature Short Time (HTST) in thermal sterilization technology. Among the indigenous species of berry-like fruit grown in Indonesia are mulberry (Morus nigra), bignay (Antidesma bunius), and jambolana (Syzygium cumini). This berry-like fruits possess great potential as raw materials for juice industries. In order to evaluate the applicability of ohmic technology for sterilization of juice and purees from these fruits, a stationary ohmic heating system has been built and tested on these three types of fruit juice. The electrical conductivities, heating rates, and system performance coefficients were measured. This study found that the electrical conductivities of all these fruit juices were ranging from 0.128 to 0.430 S.m−1 which increased linearly with temperature. The heating rates were 0.57-0.66 °C/s and the SPC values were ranging from 0.64 - 0.81. This study concluded that ohmic heating is suitable for sterilization of these three types of fruit juices as it could provide a short heating time and a high coefficient of performance. However, the designed ohmic heating system seems to suit better for jambolana juice than for mulberry and bignay juice.

Recent developments in ohmic technology for clean label fruit and vegetable processing: An overview

“…(Shao et al, 2021). Recently, many authors described the pasteurization impact of OH technology for the processing of blended citrus juices (Hashemi & Roohi, 2019), carrot juices (Negri Rodríguez et al, 2021), grape juices (Kumar, 2020), cashew apple juice (Ashitha, Prince, & Sudheer, 2020), madan juices (Khuenpet & Jittanit, 2020), mulberry, bignay, and jambolana juices (Hardinasinta, Salengke, Mursalim, & Muhidong, 2021). In the context of phenolic compounds stability during OH pasteurization (20.5 V/cm), changing waveforms (square and pulsed) promoted higher degradation rather than changing voltage and electric field frequencies (Brochier, Mercali, & Marczak, 2018).…”

Effect of Ohmic Heating on the Rheological Characteristics and Electrical Conductivity of Mulberry (Morus nigra) Puree

“…This study further explained that the non-uniformity of cell cluster surface led to the agglomeration of cells into larger clusters and therefore increased the viscosity of puree. The heat applied during ohmic processing could lead to the membrane destruction inside the cells and cause structural changes of the sample [Castro et al, 2004;Hardinasinta et al, 2021]. The structural changes that happened during heating are the main reason for the different trend shown by the K-value of the control sample and the ohmic-treated sample (Table 3).…”

“…The implementation of ohmic heating in various processes has been reported in numerous studies. These processes include pasteurization and sterilization [Cappato et al, 2018;Hardinasinta et al, 2021], evaporation [Sabanci & Icier, 2020], blanching and pre-treatment [Mannozzi et al, 2019], extraction [Hasizah et al, 2018], thawing [Fattahi & Zamindar, 2020], and fermentation [Salengke et al, 2019]. Studies evaluating the application of ohmic heating for food processing mainly focused on the change in electrical conductivity, bioactive compound profile, antioxidant activity, color, and enzymatic inactivation in correlation to the product composition.…”