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Universitas Sumatera Utara

UniversityMedan, North Sumatra, Indonesia

Research output, citation impact, and the most-cited recent papers from Universitas Sumatera Utara (Indonesia). Aggregated across the NobleBlocks index of 300M+ scholarly works.

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40.0K
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290.4K
h-index
113
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6.9K
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Universitas Sumatera UtaraUniversity of North Sumatra

Top-cited papers from Universitas Sumatera Utara

Terpenes and terpenoids as main bioactive compounds of essential oils, their roles in human health and potential application as natural food preservatives
Ayu Masyita, Reka Mustika Sari, Ayun Dwi Astuti, Budiman Yasir +4 more
2022· Food Chemistry X956doi:10.1016/j.fochx.2022.100217

Essential oils (EOs) are volatile and concentrated liquids extracted from different parts of plants. Bioactive compounds found in EOs, especially terpenes and terpenoids possess a wide range of biological activities including anticancer, antimicrobial, anti-inflammatory, antioxidant, and antiallergic. Available literature confirms that EOs exhibit antimicrobial and food preservative properties that are considered as a real potential application in food industry. Hence, the purpose of this review is to present an overview of current knowledge of EOs for application in pharmaceutical and medical industries as well as their potential as food preservatives in food industry.

Dampak Pandemi COVID-19 terhadap Perekonomian Indonesia
Dito Aditia Darma Nasution, Erlina Erlina, Iskandar Muda
2020· Jurnal Benefita624doi:10.22216/jbe.v5i2.5313

<p><em>This study aims to determine the impact of the COVID-19 pandemic on the Indonesian economy. Until this research was written, 93 countries were found infected with COVID-19. The spread of COVID-19 which had spread eventually brought very bad risks to the world economy, including Indonesia, especially in terms of tourism, trade and investment. The method used in this research is descriptive quantitative method that uses an approach called secondary data analysis, which is a research methodology that uses secondary data as the main data source. Based on the results of the study, Indonesia is currently still in a stable economic situation. Strategic steps related to fiscal and monetary are also estimated to still have room to provide economic stimulus if needed. However, as the COVID-19 pandemic case developed, the market did fluctuate more in the negative direction. Not only that, the slow pace of Indonesia's export activities to China will also have a significant impact on the economy in Indonesia.</em></p><p><em><br /></em></p><p><em>Penelitian ini bertujuan untuk mengetahui dampak pandemi COVID-19 terhadap perekonomian Indonesia. Hingga penelitian ini ditulis ditemukan 93 negara yang telah terjangkit COVID-19. Pandemi COVID-19 yang telah menyebar pada akhirnya membawa risiko yang sangat buruk bagi perekonomian dunia termasuk Indonesia khususnya dari sisi pariwisata, perdagangan serta investasi. Metode yang digunakan dalam penelitian ini adalah metode kuantitatif deskriptif dengan menggunakan pendekatan analisis data sekunder. Berdasarkan hasil penelitian, dampak pandemi COVID-19 menyebabkan rendahnya sentimen investor terhadap pasar yang pada akhirnya membawa pasar ke arah cenderung negatif. Langkah-langkah strategis terkait fiskal dan moneter sangat dibutuhkan untuk memberikan rangsangan ekonomi. Seiring berkembangnya kasus pandemi COVID-19, pasar lebih berfluktuasi ke arah yang negatif. Tidak hanya itu saja, lambatnya ekonomi global khususnya kegiatan ekspor Indonesia ke China juga berdampak signifikan terhadap perekonomian Indonesia. Hal tersebut berdasarkan analisis sensitivitas yang menjelaskan bahwa lambatnya ekonomi global saat ini sangat berdampak terhadap pertumbuhan perekonomian Indonesia.</em></p>

Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics
J. W. Ferry Slik, Gary D. Paoli, Krista L. McGuire, Iêda Leão do Amaral +4 more
2013· Global Ecology and Biogeography541doi:10.1111/geb.12092

Abstract Aim Large trees (d.b.h. ≥ 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan‐tropical scales. Location Pan‐tropical. Methods Aboveground biomass ( AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights ( AICc ‐wi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB /density of large trees and environmental and species trait variables correcting for spatial autocorrelation. Results Density of large trees explained c . 70% of the variation in pan‐tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean) ± 105.0 ( SD ) M g ha −1 ] versus Palaeotropical forests (Africa 418.3 ± 91.8 M g ha −1 ; Asia 393.3 ± 109.3 M g ha −1 ). Pan‐tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents. Main conclusions Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in‐depth analyses of the community dynamics of large trees.

New Route to Synthesize of Graphene Nano Sheets
Rikson Siburian, Hengki Tamando Sihotang, S. Raja, Minto Supeno +1 more
2018· Oriental Journal Of Chemistry487doi:10.13005/ojc/340120

Oriental Journal of Chemistry is a peer reviewed quarterly research journal of pure and applied chemistry. It publishes standard research papers in almost all thrust areas of current chemistry of academic and commercial importance. It provides a platform for rapid publication of quality research papers, reviews and chemistry letters. Oriental Journal of Chemistry is abstracted and indexed in almost all reputed National and International agencies.

An estimate of the number of tropical tree species
Ferry Slik, Víctor Arroyo‐Rodríguez, Shin‐ichiro Aiba, Patricia Álvarez-Loayza +4 more
2015· Proceedings of the National Academy of Sciences479doi:10.1073/pnas.1423147112

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

Impact of COVID-19’s Pandemic on the Economy of Indonesia
Susilawati Susilawati, Reinpal Falefi, Agus Purwoko
2020· Budapest International Research and Critics Institute (BIRCI-Journal) Humanities and Social Sciences404doi:10.33258/birci.v3i2.954

COVID-19 is a global health problem including in Indonesia. The increased case of COVID-19 proved to have quite a significant impact on the economy globally which may have affected stability in Indonesia. This method of collecting data is a method of study literature with secondary data types. Data is taken from the Internet with respect to the validity of information such as government official information, official online sites and processed results of valid data. After obtaining the existing reference, a sorting of information that is appropriate to the topic of discussion. Data analysis is presented in graphical form and comes with a descriptive narrative. Based on the research, the impact of COVID-19 pandemic affects the economy in Indonesia. The affected sectors during the COVID-19 pandemic are transportation, tourism, trade, health and other sectors, but the economic sector most affected by COVID-19 is the household sector. Optimizing the potential in the country, the decline of BI-7 Day Reverse Repo Rate (BI7DRR), the interest rate of Deposit facility, and Lending facility interest rate, monitoring of global and domestic economic development conducted by Indonesia was assessed precisely so that inflation and stability remain in control.

A Review on Emerging Pollutants in the Water Environment: Existences, Health Effects and Treatment Processes
Nor Zaiha Arman, Salmiati Salmiati, Azmi Aris, Mohd Razman Salim +3 more
2021· Water268doi:10.3390/w13223258

Emerging pollutants (EPs), also known as micropollutants, have been a major issue for the global population in recent years as a result of the potential threats they bring to the environment and human health. Pharmaceuticals and personal care products (PPCPs), antibiotics, and hormones that are used in great demand for health and cosmetic purposes have rapidly culminated in the emergence of environmental pollutants. EPs impact the environment in a variety of ways. EPs originate from animal or human sources, either directly discharged into waterbodies or slowly leached via soils. As a result, water quality will deteriorate, drinking water sources will be contaminated, and health issues will arise. Since drinking water treatment plants rely on water resources, the prevalence of this contamination in aquatic environments, particularly surface water, is a severe problem. The review looks into several related issues on EPs in water environment, including methods in removing EPs. Despite its benefits and downsides, the EPs treatment processes comprise several approaches such as physico-chemical, biological, and advanced oxidation processes. Nonetheless, one of the membrane-based filtration methods, ultrafiltration, is considered as one of the technologies that promises the best micropollutant removal in water. With interesting properties including a moderate operating manner and great selectivity, this treatment approach is more popular than conventional ones. This study presents a comprehensive summary of EP’s existence in the environment, its toxicological consequences on health, and potential removal and treatment strategies.

Hydrogel and Effects of Crosslinking Agent on Cellulose-Based Hydrogels: A Review
Halimatuddahliana Nasution, Hamidah Harahap, Nisaul Fadilah Dalimunthe, Muhammad Hendra Sahputra Ginting +4 more
2022· Gels267doi:10.3390/gels8090568

Hydrogels are hydrophilic polymer materials that can swell but are insoluble in water. Hydrogels can be synthesized with synthetic or natural polymers, but natural polymers are preferred because they are similar to natural tissues, which can absorb a high water content, are biocompatible, and are biodegradable. The three-dimensional structure of the hydrogel affects its water insolubility and ability to maintain its shape. Cellulose hydrogels are preferred over other polymers because they are highly biocompatible, easily accessible, and affordable. Carboxymethyl cellulose sodium (CMCNa) is an example of a water-soluble cellulose derivative that can be synthesized using natural materials. A crosslinking agent is used to strengthen the properties of the hydrogel. Chemical crosslinking agent is used more often than physical crosslinking agent. In this review, article, different types of crosslinking agents are discussed based on synthetic and natural crosslinking agents. Hydrogels that utilize synthetic crosslinking agent have advantages, such as adjustable mechanical properties and easy control of the chemical composition. However, hydrogels that use natural crosslinking agent have better biocompatibility and less latent toxic effect.

Challenges of blockchain technology adoption for e-government
Fakhruddin Rizal Batubara, Jolien Ubacht, Marijn Janssen
2018239doi:10.1145/3209281.3209317

The ability of blockchain technology to record transactions on distributed ledgers offers new opportunities for governments to improve transparency, prevent fraud, and establish trust in the public sector. However, blockchain adoption and use in the context of e-Government is rather unexplored in academic literature. In this paper, we systematically review relevant research to understand the current research topics, challenges and future directions regarding blockchain adoption for e-Government. The results show that the adoption of blockchain-based applications in e-Government is still very limited and there is a lack of empirical evidence. The main challenges faced in blockchain adoption are predominantly presented as technological aspects such as security, scalability and flexibility. From an organizational point of view, the issues of acceptability and the need of new governance models are presented as the main barriers to adoption. Moreover, the lack of legal and regulatory support is identified as the main environmental barrier of adoption. Based on the challenges presented in the literature, we propose future research questions that need to be addressed to inform how the public sector should approach the blockchain technology adoption.

Anticancer and health protective properties of citrus fruit components
Jansen Silalahi
2002· Asia Pacific Journal of Clinical Nutrition238doi:10.1046/j.1440-6047.2002.00271.x

Accumulated evidence from experimental and epidemiological studies indicates that there is a low risk of degenerative diseases, cardiovascular disease, hypertension, cataract, stroke and, in particular, cancers in people with a high intake of fruit and vegetables. This protective effect is assumed to be associated mainly with the antioxidant activities of either individual or interacting bioactive components present in the fruits and vegetables, and with other biochemical and physical characteristics of the identified and unknown bioactive components. The implicated bioactive components present in citrus fruits include vitamin C, beta-carotene, flavonoids, limonoids, folic acid, and dietary fibre. A high intake of citrus fruits may reduce the risk of degenerative diseases.

A current advancement on the role of lignin as sustainable reinforcement material in biopolymeric blends
Mariana Mariana, Tata Alfatah, H. P. S. Abdul Khalil, Esam Bashir Yahya +4 more
2021· Journal of Materials Research and Technology206doi:10.1016/j.jmrt.2021.08.139

Recently, the demand for biodegradable, eco-friendly and sustainable alternatives has been on the increase. Although numerous biopolymers such as cellulose, starch, plants proteins and polylactic acid, etc., have been used to produce bioplastics, the outcomes need more improvement to suit different applications. This paper comprehensively maps the expanding academic territory using lignin as a reinforcement material to improve biopolymers-based materials' properties. A brief discussion on the chronological development of lignin, types, isolation, physical and chemical modifications was presented. Also, the role of lignin in biopolymeric blends such as starch, polylactic acids, plants proteins, polyhydroxy butyrate and polyamides was reviewed. Finally, the review extensively and critically discusses the current findings on lignin/biopolymers blends in various industrial applications, including wood adhesives, adsorbent for toxic heavy metal removal, production of carbon materials, dispersant medium, flame retardant and storage materials, etc., and highlighted the possible applications of lignin in biofuel, hydrocarbon, lubricant, renewable chemical, and smart materials.

RETRACTED ARTICLE: A paradigm shift in cell-free approach: the emerging role of MSCs-derived exosomes in regenerative medicine
Soudeh Moghadasi, Marischa Elveny, Heshu Sulaiman Rahman, Wanich Suksatan +4 more
2021· Journal of Translational Medicine204doi:10.1186/s12967-021-02980-6

Recently, mesenchymal stem/stromal cells (MSCs) due to their pro-angiogenic, anti-apoptotic, and immunoregulatory competencies along with fewer ethical issues are presented as a rational strategy for regenerative medicine. Current reports have signified that the pleiotropic effects of MSCs are not related to their differentiation potentials, but rather are exerted through the release of soluble paracrine molecules. Being nano-sized, non-toxic, biocompatible, barely immunogenic, and owning targeting capability and organotropism, exosomes are considered nanocarriers for their possible use in diagnosis and therapy. Exosomes convey functional molecules such as long non-coding RNAs (lncRNAs) and micro-RNAs (miRNAs), proteins (e.g., chemokine and cytokine), and lipids from MSCs to the target cells. They participate in intercellular interaction procedures and enable the repair of damaged or diseased tissues and organs. Findings have evidenced that exosomes alone are liable for the beneficial influences of MSCs in a myriad of experimental models, suggesting that MSC- exosomes can be utilized to establish a novel cell-free therapeutic strategy for the treatment of varied human disorders, encompassing myocardial infarction (MI), CNS-related disorders, musculoskeletal disorders (e.g. arthritis), kidney diseases, liver diseases, lung diseases, as well as cutaneous wounds. Importantly, compared with MSCs, MSC- exosomes serve more steady entities and reduced safety risks concerning the injection of live cells, such as microvasculature occlusion risk. In the current review, we will discuss the therapeutic potential of MSC- exosomes as an innovative approach in the context of regenerative medicine and highlight the recent knowledge on MSC- exosomes in translational medicine, focusing on in vivo researches.

Phylogenetic classification of the world’s tropical forests
Ferry Slik, Janet Franklin, Víctor Arroyo‐Rodríguez, Richard Field +4 more
2018· Proceedings of the National Academy of Sciences195doi:10.1073/pnas.1714977115

Significance Identifying and explaining regional differences in tropical forest dynamics, structure, diversity, and composition are critical for anticipating region-specific responses to global environmental change. Floristic classifications are of fundamental importance for these efforts. Here we provide a global tropical forest classification that is explicitly based on community evolutionary similarity, resulting in identification of five major tropical forest regions and their relationships: ( i ) Indo-Pacific, ( ii ) Subtropical, ( iii ) African, ( iv ) American, and ( v ) Dry forests. African and American forests are grouped, reflecting their former western Gondwanan connection, while Indo-Pacific forests range from eastern Africa and Madagascar to Australia and the Pacific. The connection between northern-hemisphere Asian and American forests is confirmed, while Dry forests are identified as a single tropical biome.

Recent progress in ultra-low formaldehyde emitting adhesive systems and formaldehyde scavengers in wood-based panels: a review
Lubos Kristak, Petar Antov, Pavlo Bekhta, Muhammad Adly Rahandi Lubis +4 more
2022· Wood Material Science and Engineering190doi:10.1080/17480272.2022.2056080

Traditional wood-based panels are produced with synthetic, formaldehyde-based adhesives, commonly made from fossil-derived constituents, such as urea, phenol, melamine, etc. Along with their numerous advantages, such as chemical versatility, high reactivity and excellent adhesive performance, these adhesives are characterized by certain problems, connected with the hazardous volatile organic compounds (VOCs), mostly free formaldehyde in the adhesives and the formaldehyde emission from the finished wood composites, which is carcinogenic to humans and harmful to the environment. The growing environmental concerns and stringent legislative requirements to the formaldehyde emission from wood-based panels have posed new challenges to researchers and industrial practice, related to the development of sustainable, eco-friendly wood-based panels with close-to-zero formaldehyde emission. The most common methods to reduce the formaldehyde emission from wood-based panels have been to decrease the free formaldehyde in the adhesive by modifying the adhesive (like lowering the molar ratio of formaldehyde to urea in UF resin) or by using formaldehyde scavengers, one group of scavengers being for adhesives by mixing or reacting and the second one scavengers for wood-based panels as post-treatments. Another way is to use alternative bio-based adhesives, however, there are still substantial challenges for the complete replacement of formaldehyde-based adhesives with bio-based adhesives, mainly because of their relatively low bonding strength, poor water resistance, etc. This article presents a review and analysis of the current state of research in the field of low formaldehyde emission wood adhesives and formaldehyde scavengers for manufacturing low-toxic, eco-friendly wood composites.

Short-course primaquine for the radical cure of Plasmodium vivax malaria: a multicentre, randomised, placebo-controlled non-inferiority trial
Walter Taylor, Kamala Thriemer, Lorenz von Seidlein, Prayoon Yuentrakul +4 more
2019· The Lancet183doi:10.1016/s0140-6736(19)31285-1

BACKGROUND: Primaquine is the only widely used drug that prevents Plasmodium vivax malaria relapses, but adherence to the standard 14-day regimen is poor. We aimed to assess the efficacy of a shorter course (7 days) of primaquine for radical cure of vivax malaria. METHODS: We did a randomised, double-blind, placebo-controlled, non-inferiority trial in eight health-care clinics (two each in Afghanistan, Ethiopia, Indonesia, and Vietnam). Patients (aged ≥6 months) with normal glucose-6-phosphate dehydrogenase (G6PD) and presenting with uncomplicated vivax malaria were enrolled. Patients were given standard blood schizontocidal treatment and randomly assigned (2:2:1) to receive 7 days of supervised primaquine (1·0 mg/kg per day), 14 days of supervised primaquine (0·5 mg/kg per day), or placebo. The primary endpoint was the incidence rate of symptomatic P vivax parasitaemia during the 12-month follow-up period, assessed in the intention-to-treat population. A margin of 0·07 recurrences per person-year was used to establish non-inferiority of the 7-day regimen compared with the 14-day regimen. This trial is registered at ClinicalTrials.gov (NCT01814683). FINDINGS: Between July 20, 2014, and Nov 25, 2017, 2336 patients were enrolled. The incidence rate of symptomatic recurrent P vivax malaria was 0·18 (95% CI 0·15 to 0·21) recurrences per person-year for 935 patients in the 7-day primaquine group and 0·16 (0·13 to 0·18) for 937 patients in the 14-day primaquine group, a difference of 0·02 (-0·02 to 0·05, p=0·3405). The incidence rate for 464 patients in the placebo group was 0·96 (95% CI 0·83 to 1·08) recurrences per person-year. Potentially drug-related serious adverse events within 42 days of starting treatment were reported in nine (1·0%) of 935 patients in the 7-day group, one (0·1%) of 937 in the 14-day group and none of 464 in the control arm. Four of the serious adverse events were significant haemolysis (three in the 7-day group and one in the 14-day group). INTERPRETATION: In patients with normal G6PD, 7-day primaquine was well tolerated and non-inferior to 14-day primaquine. The short-course regimen might improve adherence and therefore the effectiveness of primaquine for radical cure of P vivax malaria. FUNDING: UK Department for International Development, UK Medical Research Council, UK National Institute for Health Research, and the Wellcome Trust through the Joint Global Health Trials Scheme (MR/K007424/1) and the Bill & Melinda Gates Foundation (OPP1054404).

Latest advancements in high-performance bio-based wood adhesives: A critical review
M. Hazwan Hussin, Nur Hanis Abd Latif, Tuan Sherwyn Hamidon, Nor Najhan Idris +4 more
2022· Journal of Materials Research and Technology180doi:10.1016/j.jmrt.2022.10.156

Over the last 50 years, the use of wood adhesives in the manufacturing of wood-based panel goods has increased the efficiency of wood resources. Wood adhesives are becoming more popular as the need for wood-based panels grows. By 2028, the global market for wood adhesives is expected to reach 21.8 billion dollars. Even though urea-formaldehyde (UF), phenol-formaldehyde (PF), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), and resorcinol-formaldehyde (RF) resins are excellent in terms of bonding performance, workability, quality, and economy, they consist of harmful or toxic chemical agents derived from fossil resources, which make their application severely limited. This review aims to go through the most significant ‘green’ wood adhesives for manufacturing high-performance wood-based panels, such as lignin, tannin, protein, natural rubber, emulsion polymer isocyanate (EPI), 1C PUR polyurethane (for glue-laminated wood and cross-laminated timber), PMDI (for particleboards, medium-density and low-density fiberboards), carboxylic acid, and vegetable oil. The physical and mechanical characteristics of bio-based wood adhesives, as well as the development of sustainable, greener, and high-performance bio-based wood adhesives, are discussed in this work. Original research papers and review articles are among the most important sources since they provide complete information on the most recent developments in sustainable, eco-friendly, and high-performance bio-based wood adhesives.

Impact of COVID-19 large scale restriction on environment and economy in Indonesia
Rezzy Eko Caraka, Youngjo Lee, Robert Kurniawan, Riki Herliansyah +4 more
2020· Research Explorer (The University of Manchester)177doi:10.22034/gjesm.2019.06.si.07

COVID-19 has a severe and widespread impact, especially in Indonesia. COVID-19 was first reported in Indonesia on March 03, 2020 then rapidly spread to all 34 provinces by April 09, 2020. Since then, COVID-19 is declared a state of national disaster and health emergency. This research analyzes the difference of CO, HCHO, NO2, and SO2 density in Jakarta, West Java, Central Java, and South Sulawesi before and during the pandemic. Also, this study assesses the effect of large scale restrictions on the economic growth during COVID-19 pandemic in Indonesia. In a nutshell, the results on Wilcoxon and Fisher test by significance level α=5% as well as odds ratio showed that there are significant differences of CO density in all regions with highest odds ratio in East Java (OR=9.07), significant differences of HCHO density in DKI Jakarta, East Java, and South Sulawesi. There are significant differences of NO2 density before and during public activities limitation in DKI Jakarta, West Java, East Java, and South Sulawesi. However, the results show that there are no significant differences of SO2 density in all regions. In addition, this research shows that there are significant differences of retail, grocery and pharmacy, and residental mobility before and during the COVID-19 pandemic in Indonesia. This research also shows that during the COVID-19 pandemic there are severe economic losses, industry, companies, and real disruptions are severe for all levels of life due to large scale restrictions.

Effects of milk pH alteration on casein micelle size and gelation properties of milk
Hotnida Sinaga, Nidhi Bansal, Bhesh Bhandari
2016· International Journal of Food Properties175doi:10.1080/10942912.2016.1152480

The effects of changes in pH above and below the natural pH of milk (ca 6.6) on the casein micelle size and the gelation properties of the pH adjusted and restored samples were investigated. The size of casein micelles increased at pH 7.0 and 7.5, then started to decrease above pH 8.5. It is postulated that at pH below 8.5 the casein micelles swell, while elevated pH causes their dissociation. Conversely, the size of casein micelles decreased on acidification to pH 5.5 and increased when the pH dropped below 5.5, due to the shrinkage of casein micelles at lower pH before their aggregation at pH below 5.5. In response to neutralising treated milk back to normal milk pH of 6.6, it was found that the casein micelle size of treated milk with a narrow range of pH change between 6.0 and 7.0 was reversible, while beyond this range the structure of casein micelles became irreversible. The restoration of casein micelle size was followed by the restoration of some parameters such as soluble calcium, ethanol stability, and milk whiteness. Acid-induced gelation did not change the elastic modulus, while rennet-induced gelation was affected by initial milk pH. In reference to the size of reversible range elastic modulus (G’) of acid or rennet gels made from restored milk, the sizes were similar to control milk after 6 h of gelation.

Banana stem based activated carbon as a low-cost adsorbent for methylene blue removal: Isotherm, kinetics, and reusability
Erni Misran, Okta Bani, E M Situmeang, Adelina Suciani Purba
2021· Alexandria Engineering Journal169doi:10.1016/j.aej.2021.07.022

A low-cost activated carbon from the banana stem (ACBS) was produced to contribute to environmental preservation in removing methylene blue from wastewater. It is originated from abundant agricultural waste and produced at moderate pyrolysis temperature and short pyrolisis time. In the ACBS production, the banana stem was impregnated with H3PO4 solution as the activating agent and followed by pyrolysis at 400 °C for a rapid time of 15 min. The treatment significantly improved the ACBS surface area to 837.453 m2/g. The influence of the ACBS dose and initial concentration of dye solution at various contact times were investigated in this study. The utilization of ACBS in low doses exhibited high removal efficiency of methylene blue (0.05 to 0.3 g/100 mL). It can remove methylene blue completely in 90 min of adsorption with an initial concentration of 50 g/mL. High removal efficiencies are still also demonstrated at higher initial concentrations with 99.762% removal for the initial concentration of 200 g/mL. Equilibrium adsorption data had the best agreement to the Freundlich isotherm model and pseudo-second-order kinetics model. It is predicted that ACBS has a maximum adsorption capacity of 101.01 mg/g. ACBS is an environmentally benign and favorable adsorbent in methylene blue removal and also effective for repeated usage up to 6 consecutive times with no desorption step.

Functional and rheological properties of composite flour from sweet potato, maize, soybean and xanthan gum
Elisa Julianti, Herla Rusmarilin, Ridwansyah Ridwansyah, Era Yusraini
2015· Journal of the Saudi Society of Agricultural Sciences157doi:10.1016/j.jssas.2015.05.005

Sweet potato flour (SP), maize starch (MS), and soybean flour (SF) blends were prepared in different proportions like: 60SP/20MS/19.5SF; 50SP/30MS/19.5SF; 40SP/40MS/19.5SF; 50SP/20MS/29.5SF; 40SP/20MS/29.5SF; and 30SP/40MS/29.5SF. The constant percentage of xanthan gum at 0.5% was added to each blend. Functional and rheological properties of the composite flour were examined and compared with wheat flour as control. Oil absorption index was not significantly different (P > 0.05) among the six blends of composite flour and wheat flour. As increasing of soybean flour levels, swelling power, and pasting viscosity of composite flours decreased, specific volume of bread also decreased as decreasing of soybean flour level in composite flours, but the firmness of bread increased. Physical and sensory analysis showed that composite flour with the proportion of sweet potato flour 40%, maize starch 40%, soybean flour 19.5% and xanthan gum 0.5% yielded acceptable breads.