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The quality charcteristics of rice could be changed during storage caused by respiration and enzyme activity. The respiration process remains during storage, producing carbon dioxides, vapour, and heat. This study aimed to examine the changes in physical and chemical properties of rice (cv. Mentikwangi) for six months of storage. Rice samples were packed using plastic polypropylene and stored at ambient temperatures of 27-30 °C and 54-62% of humidity. Rice sampling was done four times, i.e., months 0, 2, 4, and 6. Observations were made on starch crystallinity, particle morphology, reducing sugars, amylose, glucose, and maltose. The SEM image and XRD data showed that rice starch was less rigid and more amorphous after four months. In addition, eating quality data showed that the rice had high swelling and needed more water. Amylographic also performed that rice samples were getting harder. Sugar and amylose reduction levels increased by 1.84% and 2.5%, respectively. Unlike both, around 7.94% of starch was reduced. The γ-amylase had broken the amylopectin chain according to the glucose content degradation and occurred naturally during the six-month storage period.

Bromelain belongs to a group of protease enzymes which has function in the pharmaceutical field as an antiplatelet. The use of bromelain through oral administration is quite difficult because the enzyme is easily degraded by acidic stomach fluids and gastric enzymes. The bromelain must be encapsulated in glutaraldehyde-crosslinked chitosan microspheres (GCM) to maintain the activity of bromelain until it reaches the intestine. The aim of the study was to evaluate the dissolution profiles and in vitro antiplatelet activity of bromelain from partial purification of pineapple cores encapsulated in GCM. In this study, we isolated bromelain from pineapple cores by using ammonium sulfate precipitation and dialysis. Specific activities of each fraction showed an increase, ranging from crude enzymes (71.10 U/mg), ammonium sulfate fraction (151.70 U/mg) and dialysis (226.8 U/mg). By using a post-loading method, bromelain fraction from the dialysis step was encapsulated in GCM matrixes. GCM has a crosslinking degree of 94.87% and swelling ratio of 42.17% at pH 1.2; 21.90% at pH 7.4. The encapsulation efficiency of bromelain in GCM was 84.75%. Evaluation dissolution profiles of GCM-encapsulated bromelain were tested in artificial stomach fluid and intestinal environment for 10 hours. The results showed a relatively lower release rate of bromelain in artificial stomach fluid (13.43%) compared to the intestinal environment (60.52%). Proteolytic activity of bromelain could be maintained up to 0.35 U/mL in an artificial intestinal environment. FTIR and Scanning Electron Microscope are chosen for GCM-encapsulated bromelain characterization. However, the GCM released bromelain satisfactorily, with at least 74% of the bromelain dissolved within 10 hours while in vitro antiplatelet activity using platelet-rich plasma showed a good inhibition percentage of 71.88%.

This study was conducted on bromelain from pineapple core (Ananas comosus [L] Merr). The crude enzyme gained from pineapple core extract was then fractionated by (NH4)2SO4 and ethanol in different concentration levels. Fractionation using 20-50% (NH4)2SO4 resulted in the highest specific activity of 89.32 U/mg with a purity level of 1.72 times. Further purification increased its specific activity to 120.83 U/mg with a purity level of 2.32 times. Fractionation using 20-50% ethanol obtained the highest specific activity of 184.79 U/mg with a purity level of 27.15 times. Bromelain fractions with the highest specific activity were tested in vitro for their activity as antiplatelet agents using PRP (Platelet Rich Plasma). The platelet aggregation percentage of ammonium sulfate fraction was shown as 17.12% with the platelet aggregation inhibition percentage of 81.56%. The 20-50% ethanol fraction showed the platelet aggregation percentage was 15.93% with the percentage of platelet aggregation inhibition of 82.83%. The fraction of bromelain with higher specific activity showed a higher aggregate antiplatelet activity.

This study was conducted to isolate and purify bromelain from pineapple core (Ananas comosus (L.) Merr.) by multisteps fractionation using acetone and ammonium sulphate. The antibacterial activity of bromelain fraction with the highest specific activity was examined using disc diffusion method against S. mutans and P. gingivalis, bacteria that cause dental caries and periodontal disease. The crude enzyme showed proteolitic activity with the specific activity of 52.318 Unit/mg. Fractionation of crude enzyme using acetone produced the third fraction with level of saturation of 50-80 % that has a highest specific activity of 87.778 Unit/mg. Further purification by fractionation using ammonium sulphate produced the third fraction which has a specific activity value increase to 260 Unit/mg. After dialysis, the specific activity of the ammonium sulphate third fraction was increased to 340.926 Unit/mg. The antibacterial assay showed that ammonium sulphate fraction has a strong activity against P. gingivalis bacteria with diameter of clear zone of 21 mm and weak activity against S. mutans with diameter of clear zone of 12 mm.

The aim of this study is to coat the bromelain from pineapple’s core into chitosan microspheres crosslinked by glutaraldehyde to maintain its activity until it reaches the intestines. The crude enzyme was first purified by ammonium sulfate precipitation method, followed by the dialysis. The bromelain fraction of the dialysis has a specific activity of 294.44 U/mg with a purity level of 15.68 fold compared to the crude enzyme. Coating bromelain using glutaraldehyde crosslinked microsphere showed an efficiency of 87.14 %. The dissolution test results showed the release rate of bromelain in artificial gastric fluid is 9.35 % and in artificial intestinal environment is 79.92 %. The result of this study indicates that chitosan-coated microspheres are good enough as bromelain coatings for slow-release matrices.

The aim of this study is to maintain the antiplatelet activity of pineapple core bromelain from degradation in gastric fluid by encapsulating the enzyme in alginate-guar gum crosslinked with glutaraldehyde. Bromelain isolation was followed by purification process such as ammonium sulfate precipitation and dialysis. The specific activity obtained showed an enhancement started for crude enzyme (20.11 U/mg), ammonium sulfate fraction (190.64 U/mg), and dialysis fraction (229.77 U/mg). Dialysis fraction was encapsulated by in situ loading method in alginate-guar gum hydrogel with 1.25% (v/v) glutaraldehyde concentration. The swelling ratio of the hydrogel is 234.37 % in acidity of 1.2; and 1375.91 % in acidity of 7.4; while the encapsulation efficiency amount was 60.42%. I n addition, maximum concentration of bromelain released in dissolution test was higher in artificial intestinal environment (1.79 mg/L) than in artificial gastric fluid (0.13 mg/L), with maximum proteolytic activity of 1.2 U/mL and 0.11 U/mL, respectively. In vitro study of antiplatelet activity showed a good inhibition for dialysis fraction (50.6 %) and dissolution fraction (34.86 %), indicating that the hydrogel is good enough to maintain the activity of bromelain.

Bromelain found in various tissues in the pineapple plant (Ananas Comusus [L] Merr. The bromelain will be taken from pineapple cores for kinetic study. The effect of addition organic compounds, such as phenylmethylsulfonyl fluoride (PMSF) and cysteine on its kinetics behaviour will be determined by proteolytic activities of the bromelain. The stages of this study were started from isolation of crude enzyme, fractionation with ammonium sulphate salt, dialysis, and ion-exchange column chromatography with CM sephadex C-50 for enzyme purification. The obtained enzyme fractions from crude enzyme, ammonium sulphate, dialysis, and CM-sephadex C-50 ion exchange chromatography have specific activities of 45.39, 238.31, 311.16, and 427.13 U/mg, respectively. The purification stages result in increasing of the bromelain specific activities by 9 times compared to the crude enzyme. The Michaelis-Menten constant (Km) value for the purified bromelain was 0.85 % casein and the Vmax value was 0.41 U/min. Addition of PMSF and cysteine compound effect on its Vmax and Km with various trends. The Vmax value will be decreased by addition of PMSF and increased by addition of cysteine. Thus, proteolytic activity of bromelain from pineapple cores can be significantly increased by the addition of cysteine compounds and inhibited by the addition of PMSF.

β-carotene is a compound that forms red, orange and yellow pigments in carrots. β- carotene compounds in the form of liquid extract have weaknesses that are unstable, impractical in terms of storage, and have a short shelf life so that further treatment is needed to produce β- carotene with better characteristics, one of method is encapsulation using maltodextrin. This study aims to determine the best concentration of maltodextrin β-carotene. The research method used was an experimental method with one-way analysis of variance (ANOVA) with a confidence level of 95% consisting of 3 treatments with 3 replications, namely the addition of 10%, 20%, and 30% (b/v). The results showed that β-carotene carrot powder with the addition of 20% maltodextrin produced the highest total β-carotene which was 29.160 ppm.

Nitric oxide (NO) plays an important role in physiological processes. NO measurement accuracy is important to understand the essential functions of NO but attaining these levels of accuracy is difficult due to NO’s short half-life. NO concentrations can be determined using an analytical method that has fast response and high sensitivity and is simple and practical. In this study, gold and platinum metals are deposited onto a screen-printed electrode (SPE) surface in a solution mixture of HAuCl4 in 0.05 M H2SO4 and K2PtCl6, in 0.05 M H2SO4, which has been modified with graphene to detect NO. Experiments that varied the deposition concentrations of the Au/Pt onto the G/SPE are conducted to obtain an optimal deposit concentration ratio between AuPt and G/SPE. NO detection tests are conducted at +0.878 V against Ag/AgCl. Deposits of AuPt/G/SPE that have 1:1 concentrations form high-performance sensors due to its high sensitivity at 23029.92 μA mM−1 cm−2, a low detection limit of 2.2 × 10−3 mM, and the best linearity, R2 = 0.9943. No is detected using the Griess Saltzman method. Based on the linearity results from the NO detection measurements, we observe that the electrochemical method provides significant improvements over the Griess Saltzman method.