jurnal ATMOSPHERE

THE EFFECT OF ADDITION OF SUGAR CANE JUICE AND TURMERIC ON THE PHYSIOCHYMIC AND ORGANOLEPTIC PROPERTIES OF HERBAL YOGHURT

Daratina Nafisa — 2026-06-29

Yogurt is a fermented product of cow's milk by lactic acid bacteria that has a sour taste. Making yogurt requires innovation, namely the addition of herbal ingredients such as turmeric as a natural dye and sugarcane juice as a natural sweetener. The method used in this study was the fermentation of lactic acid bacteria Lactobacillus bulgaricus and Streptococcus thermopillus. The variables used were the addition of turmeric (0.2gr, 0.4gr, and 0.6gr) and the addition of sugarcane juice (4ml, 8ml, 12ml, 16ml, and 20ml). The analysis used was pH, viscosity, lactic acid level test, density test, and organoleptic test. In the pH test, the results obtained ranged from 3.8-4.5, the lactic acid content test ranged from 0.81-0.98% b/b, the density test ranged from 1.046-1.079 g/ml, the viscosity test ranged from 14.64-53.96 cp, and the organoleptic test showed the level of preference for yoghurt with the addition of 0.2 grams of turmeric and 12 ml of sugarcane juice. Based on the results obtained, the proportion of the addition of sugarcane juice and turmeric affects the quality of yoghurt.

STUDY OF COLOR REMOVAL EFFICIENCY IN THE ADSORPTION OF ACID BLUE 29 DYE ON ACTIVATED CARBON NANOTUBES

Puguh Setyopratomo — 2026-06-29

Activated carbon nanotubes have great potential as an dyes adsorbent. This study aims to determine the removal efficiency and adsorption capacity of activated carbon nanotubes against acid blue 29 dye. Furthermore, an intraparticle diffusion kinetics model assessment will be carried out. Experiments were carried out in batches by varying the mass ratio of activated carbon nanotubes to the acid blue 29 dye solution volume. The results showed that the higher the mass ratio of activated carbon nanotubes to the liquid, the higher the removal efficiency. It was also found that the lower the mass ratio of activated carbon nanotubes to the liquid volume, the higher the adsorption capacity of activated carbon nanotubes. The intra-particle diffusion kinetics model test showed that the molecular diffusion stage of the solute within the pores of the activated carbon nanotubes is the controlling stage of the entire adsorption process.

The VARIATION OF MICROWAVE POWER AND CONCENTRATION OF BUTTERFLY PEA FLOWER IN ANTOCHIANIN EXTRACTION USING MAE METHOD

Audika Putri — 2026-06-29

Butterfly pea flower (Clitoria ternatea) contains anthocyanins, flavonoid pigments with antioxidant activity and potential as natural colorants and herbs. Anthocyanin extraction via Microwave Assisted Extraction (MAE) offers rapid extraction, reduced solvent use, and high efficiency. This study evaluated the effect of microwave power and solid-to-solvent ratio on anthocyanin extraction using ethanol acidified with 3.5% citric acid. Extractions were conducted at 100, 200, 300, and 399 W with ratios of 1:10, 1:15, 1:20, and 1:25. Extraction performance was assessed based on yield and anthocyanin content. The highest yield (18.44%) was obtained at 100 W and a 1:25 ratio, while the highest anthocyanin content (29.2 mg/100 g) was achieved at 399 W and a 1:10 ratio. The optimal condition was 300 W and a 1:20 ratio, providing a balanced extraction performance between yield and anthocyanin content.

OPTIMIZATION OF BIODIESEL PRODUCTION FROM CANDLENUT WASTE OIL VIA TWO-STEP ESTERIFICATION AND TRANSESTERIFICATION

Veronica Putri Iswono — 2026-06-29

The utilization of non-edible feedstocks is an important strategy in developing sustainable biodiesel, one of which is candlenut (kemiri) waste oil. This oil contains a high free fatty acid (FFA) level (10.05%), requiring a two-step process to prevent saponification during base-catalyzed transesterification. This study aims to develop biodiesel production through esterification using H₂SO₄ followed by transesterification using KOH. The esterification step reduces FFA via reaction with methanol, while transesterification converts triglycerides into methyl esters. The results show that FFA was successfully reduced to 0.435–0.708%. The highest ester content reached 98.98% (w/w), while total glycerol content was very low (0.0017–0.0019% w/w), indicating high conversion efficiency and product purity. Therefore, the applied two-step process effectively produces high-quality biodiesel from candlenut waste oil and demonstrates strong potential as a sustainable renewable energy source.

PRODUCTION OF BIOETHANOL FROM SPIRULINA PLATENSIS BIOMASS VIA ACID HYDROLYSIS

Muyassaroh Muyassaroh — 2026-06-29

The problem faced by the world now is the rarity of fossil fuel resources availability such as oil and natural gas, so if not switching to other renewable resources the fossil resources shall run out soon. Hence, bioethanol becomes a promising alternative in the future. One of the fuel resources becoming a favorite that can be utilized as bioethanol is spirulina platensis. Bioethanol production with Algae-based material (Spirogyra sp.) firstly is the stage of acid hydrolysis process of cellulose into glucose using HCl, H2SO4, and HNO3 with acid concentration respectively 0.1 N; 1N; 2N under temperature 80 ^oC, 90 ^oC, 100 ^oC. It continued with the stage of glucose fermentation into bioethanol by adding urea, NPK, and yeast. Next, for bioethanol purification is distillation process under temperature 78 for 4 hours. The result showed that the highest ethanol content before distillation is 0.317695% and after distillation is 10,36% occurring in the concentration of 2N H2SO4 under temperature 100 ^oC.