Jamilah Syafawati Yaacob, Nur Asniyati Abdul Halim, Sharmilla Ashokhan, Hanisah Ali and Rashidi Othman
The purpose of this study is to evaluate the pattern of carotenoids distribution in three underutilized Malaysian ‘ulam’ or traditional vegetables in Malaysia (Averrhoa carambola…
Abstract
Purpose
The purpose of this study is to evaluate the pattern of carotenoids distribution in three underutilized Malaysian ‘ulam’ or traditional vegetables in Malaysia (Averrhoa carambola, Manihot esculenta and Ipomoea batatas) and their valuable pro-vitamin A activities. These assessments will yield valuable knowledge and insight into the importance of these underutilized traditional vegetables and highlight their potential for applications in medicinal and functional colorant industries.
Design/methodology/approach
In this study, the authors have evaluated the distribution of carotenoid compounds in aerial organs of three underutilized traditional vegetables (Averrhoa carambola, Manihot esculenta and Ipomoea batatas). The content of the individual carotenoids were quantified using high-performance liquid chromatography (HPLC) and the organ with the highest accumulation of these compounds were identified. Their valuable pro-vitamin A activities were also reported to indicate their medicinal potential which can further be exploited as pharmacologically active natural colorants and in other applications.
Findings
In total, three major chromatographic peaks corresponding to lutein, violaxanthin and β-carotene were observed through HPLC. Among the compounds detected, lutein and β-carotene were the most abundant carotenoids found in both shoots and petioles of all three species. Violaxanthin was only detected in I. batatas shoots. Overall, carotenoid content was observed to be higher in the shoots than in the petioles, where I. batatas contained the highest amount of total carotenoid, followed by M. esculenta and A. carambola. The opposite trend was observed in the petioles, where A. carambola petioles had the highest carotenoid content, while I. batatas contained the least.
Research limitations/implications
The distribution and abundance of these individual carotenoids suggested that the petioles contained the highest amount of carotenoid, contributing to its high pro-vitamin A activity, and could be potentially useful for medicinal application, as it can act as storage site that is not as prone to natural drying or degradation during harvest and sample storage. Future research work should include improvements in the extraction and purification procedures as well as robust identification methods which may lead to better detection and identification of other compounds that could attribute to its bioactivity, to complement the findings of the current study.
Practical implications
This analysis provides valuable information on the importance of underutilized traditional vegetables as important biofactories for sustainable production of valuable pigments (such as carotenoids) with medicinal benefits and can further be exploited in various industries, such as in formulation of functional natural colorants. This study also highlights the importance of petiole as a storage site of pharmacologically active compounds that is not as prone to natural drying or degradation during harvest and sample storage.
Originality/value
To date, there is no previous report found on comparative analysis of carotenoid content and quantification of individual carotenoid concentration in the edible aerial parts of Averrhoa carambola, Manihot esculenta and Ipomoea batatas, although they have been traditionally consumed as “ulam” in Malaysia. Therefore, the results reported in this study provide new insights on carotenoid accumulation in the selected ‘ulam’ species.
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Hanisah Ali, Saiful Anuar Karsani, Rashidi Othman and Jamilah Syafawati Yaacob
The purpose of the present study is to understand the role of auxin and cytokinin in stimulating the production of pigmented callus in Orthosiphon stamineus and to gain…
Abstract
Purpose
The purpose of the present study is to understand the role of auxin and cytokinin in stimulating the production of pigmented callus in Orthosiphon stamineus and to gain correlation between the callus colours with their antioxidant capacity and bioactive constituents.
Design/methodology/approach
In this study, plant tissue culture was used to induce production of callus of various colours from leaf explants of O. stamineus, via manipulation of plant hormones (0-2.0 mg L−1 indole-3-acetic acid [IAA] and Kinetin [Kin]). The coloured callus was subjected to solvent extraction and used for quantification of its carotenoid, chlorophyll, anthocyanin and phenolic contents. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the extracts was also evaluated, before and after four weeks of storage at −20°C.
Findings
The highest mean (per cent) explants that produced roots (93.33 ± 0.05 per cent) were observed when the cultures were supplemented with 2.0 mg L−1 IAA. The colour of the callus changed with time, from green to cream to brown after two and four months of culture, respectively. Optimum production of green callus was achieved with addition of 2.0 mg L−1 Kin plus 1.0-2.0 mg L−1 IAA to the media, while cream callus in 0.5 mg L−1 Kin plus 2.0 mg L−1 IAA and brown callus in 0.5 mg L−1 Kin plus 1.5 mg L−1 IAA. Green callus was found to contain the highest amount of chlorophylls, carotenoid and anthocyanin, while cream callus contained the highest amount of phenolic compounds. The amount of pigments and secondary metabolites in the callus extracts decreased after four weeks of storage, except anthocyanin. The antioxidant potential of the extracts also increased after storage.
Research limitations/implications
The major compounds identified in the methanolic extracts of O. stamineus-coloured callus are chlorophylls, carotenoids, flavonoids and phenolic acids. Future research work should include improvements in the extraction and identification methods which may lead to detection of other compounds that could attribute to the antioxidant capacity, to complement the findings of the current study.
Practical implications
This analysis provides valuable information on the application of IAA and Kinetin (Kin) to manipulate the content of major pigments with medicinal benefits in O. stamineus by using the plant tissue culture system.
Originality/value
A comparative study on antioxidant capacity and bioactive constituents of pigmented callus from O. stamineus leaves is original. To the best of the authors’ knowledge, this is the first attempt of comparative evaluation on antioxidant potential of O. stamineus-coloured callus produced using IAA and Kin.
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Hanisah Mohd Zali, Mohd Khairil Adzhar Mahmood, Idnin Pasya, Miyuki Hirose and Nurulazlina Ramli
Utilization of electromagnetic wave (EMW) sensors in an underwater environment has the potential to increase the data rate compared to acoustic-based sensors because of the…
Abstract
Purpose
Utilization of electromagnetic wave (EMW) sensors in an underwater environment has the potential to increase the data rate compared to acoustic-based sensors because of the ability to use larger signal bandwidth. Nevertheless, EMW signals has the drawback of large signal attenuation in underwater, attributed to the high relative permittivity and conductivity of water compared to the atmosphere, hence employment of wide signal bandwidth is necessary to balance the data rate-attenuation trade-off. The purpose of this paper is to analyze the characteristics of both narrowband and wideband EMW signal propagation underwater and devise a path loss model for both cases.
Design/methodology/approach
Path loss measurement was conducted using a point-to-point configuration in a laboratory water tank while transmitting narrowband and wideband signals between a pair of wideband underwater antennas. The wideband underwater antennas use buffer-layer structures as the impedance matching layer to optimize the antenna performance when operating underwater. The path loss for narrowband signal was modeled using a multi-layer propagation equation in lossy medium considering losses at the medium boundaries. For the case of the wideband signal, a modified version of the model introducing power integration over bandwidth is adopted. These models were formulated through numerical simulations and verified by measurements.
Findings
The measured narrowband path loss marked an 80 dB attenuation using 800 MHz at 2 m distance. The proposed narrowband model agrees well with the measurements, with approximately 3 dB modeling error. Utilization of the proposed wideband path loss model resulted in a reduction of the gradient of the path loss curve compared to the case of the narrowband signal. The measured wideband path loss at 2 m distance underwater was approximately −65 dB, which has been shown to enable a working signal-to-noise ratio of 15 dB. This proves the potential of realizing high data rate transmission using the wideband signal.
Originality/value
The paper proposed a wideband propagation model for an underwater EMW sensor network, using power integration over bandwidth. The effectiveness of using wideband EMW signals in reducing path loss is highlighted, which is seldom discussed in the literature. This result will be of useful reference for using wideband signals in designing a high data rate transmission system in underwater wireless sensor networks, for example, in link budget, performance estimation and parameter design of suitable transmission scheme.
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Niriender Kumar Piaralal, Norazuwa Mat, Shishi Kumar Piaralal and Muhammad Awais Bhatti
The purpose of this paper is to investigate the human resource factors (rewards, training teamwork and empowerment) that affect service recovery performance (SRP) of customer…
Abstract
Purpose
The purpose of this paper is to investigate the human resource factors (rewards, training teamwork and empowerment) that affect service recovery performance (SRP) of customer service employees in life insurances companies. Life insurances industries in Malaysia are facing stiff competitions due to growing consumerism, changing consumer choices and expectations. SRP is very important aspect in the insurances firms toward retaining the customer and one of the key competitive advantages for sustainability and adding value to the organization in the future.
Design/methodology/approach
The data obtained from 350 customer service employees based on convenience sampling were analyzed using regression and hierarchical analysis.
Findings
There are two factors, namely, empowerment and training, affecting the SRP. The employment status moderated the relationship between reward and SRP. The limitations of this study have been noted and further research suggestions are also included that are very important for SRP.
Originality/value
This study has added knowledge regarding the factors that affect SRP, in general, and precisely in life insurance industries in Malaysian context.