Analysis and evaluation of the effect of reflectance values on internal walls, internal roofs, and light shelf on optimal illumination levels in the diploma economics and business building of the vocational school UGM, Yogyakarta

The use of natural light as a source of lighting in buildings is an option in energy saving. One of the efforts that has been made is the installation of a light shelf. The light shelf installed in the UGM Vocational School Economics and Business Diploma (DEB SV) building is not fully working optimally. As many as 83% of the light shelf in lecture rooms is covered by curtains because it is considered to produce excess light (glare). This results in a greater consumption of lighting electricity. This study was conducted to analyze and evaluate the effect of the reflectance value (color) attached to the internal walls, internal roof, external light shelf, and internal light shelf on the indicator of illumination levels Useful Daylight Illuminance (UDI). Furthermore, this study aims to determine the optimum reflectance value (color) parameter. The research was conducted with a simulation method using RadianceIES in the IESVE 2021 software. The first simulation results show the value of reflectance (color) installed (base case) on the internal wall, internal roof, external light shelf, and internal light shelf in one of the lecture rooms of the DEB SV UGM building resulting in a very large value of the UDI>2000lux indicator, which is 84,9% (not according to the criteria). The results of the second simulation provide two variations of the optimum reflectance (color) parameters in the independent variable. The first variation is the internal walls, internal roof, external light shelf, and internal light shelf, each of which has a reflectance value (color) of 90,67% (beige), 100% (white), 90,67% (beige), and 100% (white). The second variation is the internal walls, internal roof, exte rnal light shelf, and internal light shelf, each of which has a reflectance value (color) of 90,67% (beige), 100% (white), 90,67% (beige), and 90,67% (beige).

EFFECT OF REPEATED DEEP-FAT FRYING OF FRENCH FRIES IN SUNFLOWER AND PALM OILS ON THE ACRYLAMIDE CONTENT

The study aimed to investigate the influence of repeated frying processes of potatoes in a fryer on the acrylamide content of French fries. For deep-frying, potatoes of the Asinaria variety, sunflower and palm oils were used. For each oil type, five frying cycles at 170°C, for 6 min were performed and the acrylamide content of the final product was analyzed using the solid phase extraction (SPE) technique and the GC-MS/MS method. The acrylamide content increased in the case of sunflower oil in the first three frying cycles, while for palm oil it increased in the fourth frying cycles, then a decrease was recorded. The mean acrylamide content of French fries samples fried in sunflower oil (1477.07 μg/kg) was higher than the one of French fries fried in palm oil (1258.95 μg/kg). For all samples analyzed, the acrylamide content exceeded the benchmark level of 500 μg/kg settled by the EU 2017/2158. The acrylamide content of French fries was correlated with the color parameter L*.

The Effect of Fat Content and Fatty Acids Composition on Color and Textural Properties of Butter

The textural properties of butter are influenced by its fat content and implicitly by the fatty acids composition. The impact of butter’s chemical composition variation was studied in accordance with texture and color properties. From 37 fatty acids examined, only 18 were quantified in the analyzed butter fat samples, and approximately 69.120% were saturated, 25.482% were monounsaturated, and 5.301% were polyunsaturated. The butter samples’ viscosity ranged between 0.24 and 2.12 N, while the adhesiveness ranged between 0.286 to 18.19 N·mm. The principal component analysis (PCA) separated the butter samples based on texture parameters, fatty acids concentration, and fat content, which were in contrast with water content. Of the measured color parameters, the yellowness b* color parameter is a relevant indicator that differentiated the analyzed sample into seven statistical groups; the ANOVA statistics highlighted this difference at a level of p < 0.001.

Karakteristik Sensori, Kimia dan Fisik Pempek dari Ikan Tenggiri dan Ikan Kiter pada Berbagai Formulasi

Pempek is one of traditional snack food from Palembang which made from fish and very popular in Indonesia. The objective of this study was to determine the effect of the combination of barred mackerel fish and pickhandle barracuda fish meat on sensory, chemical and physical properties and to determine the best economic formulation of pempek. This study used the Completely Randomized Design with six level treatments of combination of barred mackerel fish and pickhandle barracuda fish, respectively, 200 g-0 g (P1), 160 g-40 g (P2), 120 g-80 g (P3), 80 g-120 g (P4), 40 g-160 g (P5), and 0 g-200 g (P6). The characteristics of pempek was observed on the sensory (color, aroma, taste, texture and overall acceptance), chemical (moisture and protein content), and physical properties (hardness, cohesiveness, springiness). The result showed that the treatment only has a significant effect on color parameter of sensory properties. The higher amount use of pickhandle barracuda fish significantly reduced the panelist preference on color. The best formulation chosen was the combination of 40 g barred mackerel fish and 160 g pickhandle barracuda with the economic total raw material cost Rp 12.750. This formulation is recommended to produce pempek with best quality and economic cost. Keywords: economic, formulation, pempek, sensory properties

Evaluation of water sorption isotherm, glass transistion temperature, vitamin C and color stability of mango peel powder during storage

The purpose of this work was to study the physical and chemical stability of the mango peel powder produced by hot-air drying. Sorption isotherms at 25 °C and glass transition temperatures (Tg) of the samples in equilibrium at different aw were determined. The degradation of vitamin C and color parameter b* was evaluated along storage under controlled conditions (relative humidity = 60%, temperature = 10, 25 and 35 °C) during 180 days. GAB model well-described water adsorption of the product, showing a monolayer moisture content (Xm) of 0.1260 g water/g dry solids and a critical aw of 0.56. The Gordon-Taylor model predicted the plasticizing effect of water on glass transition temperature, since Tg of the powders kept at different relative humidity conditions decreased as water activity increased. No visual signs of agglomeration and darkening were observed for samples stored at aw ≤ 0.529. The powders are a source of calcium and rich in potassium, copper, magnesium and manganese. The concentration of inorganic contaminants and pesticide residues were below the maximum allowed limits. The degradation of vitamin C and color parameter b* followed the first and zero-order kinetic models, respectively. The study indicated good stability for the powders along the storage at 10 and 25 °C, which can be incorporated into different food products, showing high retention of vitamin C, phenolic compounds, antioxidant activity and maintenance of color characteristics.

Relations between the ecological conditions and the properties of Pterocarpus erinaceus Poir. wood from the Guinean-Sudanian and Sahelian zones of West Africa

Pterocarpus erinaceus (Poir) is currently the most exploited and threatened spontaneous tree species in the Guinean-Sudanian and Sudano-Sahelian zones in West Africa. This work analyzed the density and color parameters of P. erinaceus wood in the phytogeographic zones (Sudanian, Guinean and Sahelian) in three countries in West Africa (Togo, Burkina Faso and Niger). The results obtained by studying 451 specimens taken from 95 trees showed significant differences in basic density and color parameter values (P < 0.001) based on phytogeographic zones. Individual tree samples from the Sahelian zone were denser (780 ± 63 kg · m − 3), darker (L* = 48.3 ± 0.6) and redder (a* = 8.2 ± 2) than those in the Guinean zone (basic density = 684 ± 53 kg · m−3; L* = 59.7 ± 0.5; a* = 6 ± 0.2) and the Sudanian zone (basic density = 725 ± 70 kg · m−3; L* = 53.7 ± 0.40; a* = 7.30 ± 0.2). At intra-tree scale, the results did not show a significant variation of basic density according to the number of rings counted from the pith (P > 0.05). This indicated that the age of the trees has little influence on the basic density of P. erinaceus wood.

COLOURING OF COFFEE GRAINS RELATED TO DIFFERENT RELATIVE HUMIDITY OF THE DRYING AIR AFTER PARTIAL DRYING

Changes in color of coffee grains are indications of occurrence of oxidative processes and biochemical changes, which can alter the taste and aroma precursors of the grains, resulting in lower beverage quality. Thus, the aim of this study was to evaluate the color characteristics of peeled coffee grains subjected to different relative humidity of the drying air after partial drying. Coffee (Coffea arabica) fruits were harvested in the cherry stage and were wet processed. The treatments were the results of the combination of three dry bulb temperatures and three dew point temperatures. The control of dew point temperature was performed only after the grains reach the partial drying. Considering the Tbd of 40 °C - 40 °C, the reduction of the Tpd (2.6 °C) increased the grains bleaching, while the increase of Tpd (16.2 °C) resulted in a more yellowish-red. Tbd of 40 °C - 35 °C and 35 °C - 35 °C are indicated for bluish-green color formation, associated with higher sensory quality. The Color Saturation (C*) of the coffee grains are highly correlated with the b* color parameter, while the tonality (Hue) is negatively correlated with the a* color parameter.

Continuous Flow UV-C Irradiation Effects on the Physicochemical Properties of Aloe vera Gel and Pitaya (Stenocereus spp.) Blend

Physicochemical properties of a blend of 10% Aloe vera gel with 5% pitaya juice subjected to UV-C doses of 16.5, 27.7, and 40 mJ/cm2 were evaluated at pH 3.5 and 5.5. Unprocessed treatments were used as the control. The a* color parameter decreased and luminosity increased at pH 3.5. The decrease in the reddish color was consistent with the decrease in total betalains content and stabilized at pH 5.5. The NMR analyses of UV-C treatments showed changes in betalains signal patterns. Polyphenolics content was significantly reduced in the UV-C treatments at pH 5.5. UV-C processing decreased the antioxidant activity 1.25 times compared to unprocessed treatments. Total sugar content was reduced as the UV-C dose increased. Doses above 16.5 mJ/cm2 resulted in a higher simple sugar content at a pH 3.5. The UV-C continuous flow technology can be applied to stabilize betalains in Aloe vera–pitaya blends at a UV-C dose of 16.5 mJ/cm2 and pH 5.5.