Duku (Lansium domesticum), tropical exotic fruit, was successfully preserved by drying using exposure to infrared radiation emitters. Response surface methodology (RSM) is used to optimize independent variables (IRE distance of 6 cm and 10 cm, IRE temperature of 200 °C, 300 °C, 400 °C, and IRE exposure time of 50 s, 60 s, 70 s, and to produce response variables (weight loss, fruit firmness, titratable acidity, total soluble solid, and browning index).  It could be concluded from the optimization performed that drying duku skin in a whole fruit by exposing the fruit to the infrared emitter resulted in a duku fruit with a relatively good physical and chemical conditions and still be consumable. The IRE distance of 6 cm gave a desirability value of 0.80 while the IRE distance of 10 cm gave a desirability value of 0.92 however the IRE distance of 6 cm gave a better storage time.  The IRE distance of 6 cm has an optimum value of weight loss 2.2%; optimum value of fruit firmness of 40.92 N; optimum value of total soluble solid of 17.48 brix; optimum value of titratable acidity of 0.33%; and optimum value of browning index of 0.9. The fitting model base on RSM resulted from this research indicated that this study could be used as the basis for alternative process in food processing of duku but still need further research to increase the shelf life and a better result in the chemical and physical characteristics of duku.

Infrared radiation has a potential for drying agricultural commodities such as the peel of duku. Drying of duku's peel in a whole duku using infrared radiation could become an effective method to eliminate the water on the peel but not in the flesh and could increase the shelf life of duku. The objective of this study was to investigate the potential of using infrared radiation for drying the peel of duku which would increase the shelf life of duku during storage. Duku's peel drying process was achieved by means of heating duku using a pairs of electric infrared emitters (IRE) facing each other with the emitter distance of 6 cm and 10 cm for a relatively short heating time of 50, 60, 70 and 80 seconds and after that stored at a cool room at the temperature of 15 °C for the length of one month. During storage, the physical and chemical changes of duku were then evaluated. It was found that the weight loss, fruit firmness, and total soluble solid of duku dried by means of exposing to Infra Red Emitter (IRE) were significantly affected by the distance of IRE, the temperature of IRE and the time exposed to IRE. However the titratable acidity only affected significantly by the distance of IRE. There were no significantly changes of browning index on duku during drying by exposing to IRE and while stored up to 25 th day of storage. Drying duku by exposing it to IRE show a slightly better shelf life than the previous work.

The Infrared method has the potential to extend the shelf life of duku fruit by drying the duku’s skin into "shell likeness". Duku’s skin drying using infrared method could change the shape and characteristics of duku’s skin which would significantly affect the length of fruit shelf life. The texture of duku’s skin for the treatment of infrared emitter distance of 6 cm, temperature of 400 °C and exposure time of 80 seconds was increasing with the storage time which made the fruit inside the skin to experience a passive modified atmosphere and increase the shelf life of duku. The 3D visual depiction of the optimization result on drying process using infrared had the largest porosity and cavity value in the treatment of infrared emitter distance of 10 cm, temperature of 300 °C, and exposure time of 80 seconds. At the magnification of 2500 times, with a resolution of 10 mm, it was found that the porosity and thickness of the duku’s void were greater than duku fruit without treatment. The result of the porosity also found that drying process with the infrared emitter distance of 6 cm at temperature of 400 °C, and exposure time of 80 seconds has more stable porosity (without collapsing) which confirmed the result found on the texture of the skin. The results of scanning electron microscopy analysis and 3D visual analysis confirmed the results of optimization that had previously performed in the drying process of duku fruit using infrared method.

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This research has investigated the physical properties (volume expansion, texture) and microstructure of 'kemplang Palembang', traditional fish puffed crackers from Indonesia which were puffed using the microwave-oven method. The microwave-oven method was designed by the factorial randomised block design (FRBD) which contains egg addition as factors (A1 – control; A2 – egg yolk; A3 – egg white and egg yolk) and moisture factors (B1 – 7.5 ± 1%; B2 – 13.5 ± 1%). The results revealed that the egg addition and moisture were significant (P < 0.05) to the volume expansion and texture. Meanwhile, the microstructure of kemplang Palembang was evidenced by 3D visual analysis using the scanning electron microscopy (SEM) technique. The microstructural analysis by SEM showed that the porosity caused a significant change in volume expansion and texture. The results suggest the feasibility of adding eggs and moisture 13.5 ± 1% (A1B2 treatment) for proper volume expansion (523%), texture [156.2 gram-force (gf)], and microstructure.

Butterfly-pea (Clitoria ternatea L.) extract powder is a functional product with numerous benefits obtained by extraction followed by the drying process. During drying, encapsulations can be added to protect the color and antioxidants of the samples. Using visible-near-infrared (Vis–NIR) spectroscopy, this research aimed to detect maltodextrin and soybean protein isolate (SPI) added as encapsulants to butterfly-pea extract powder. Butterfly-pea extract powder were added with 10, 20, 30, 40, and 50% concentrations of maltodextrin and SPI. Spectral data were acquired using a Vis–NIR fiber optic spectrometer at 350–1,000 nm. The chemometric methods used were principal component analysis (PCA), PCA-discriminant analysis (PCA–DA), partial least square regression (PLSR), and partial least square discriminant analysis (PLS-DA). The results showed that PCA can discriminate pure and maltodextrin- and SPI-added samples using low principal components. PCA-DA determined the accuracy levels of 88% for maltodextrin and 94.67% for SPIs. The PLSR models predicted the addition of maltodextrin with the following variables: coefficient of determination of calibration (R c 2), 0.98; coefficient of determination of prediction (R p 2), 0.98; root mean square error of calibration (RMSEC), 2.1%; and root mean square error of prediction (RMSEP), 4.02%. The values for the addition of SPI were R c 2 of 0.97, R p 2 of 0.97, RMSEC of 2.72%, and RMSEP of 2.83%. The PLS-DA models resulted in an accuracy of 98 and 91% for the identification of maltodextrin and SPI, respectively. In conclusion, this research showed the potency of Vis–NIR spectroscopy combined with a proper chemometric analysis to detect additives in butterfly-pea extract powders.

Sweet potato is a local food ingredient that needs to be preserved and its benefits are because it contains a high source of starch with anthocyanins. The utilization of local ingredients is still rarely used due to limited knowledge of sweet potato processing techniques. The purpose of this study is to create innovations by developing purple sweet potato food cultivation as a natural dye in the formulation of yogurt products through hedonic testing. The research was conducted using a Randomized Block Design (RAK) method with 4 treatments consisting of 4 levels, namely A = 0 mg, B = 5 mg, C = 10 mg dan D = 15 mg, repeated 3 times. The most preferred yogurt by the panelists was yogurt with 15 mg of purple sweet potato extract added, with a value of 3.78 for taste, 3.01 for flavor and 3.53 for color. With a protein content of 4.76 gr, fat 12.60 gr, 13.2 gr, anthocyanins 14.42 mg (in 100 mL), and antioxidant activity of 3851.13 ppm.

This study compared the calibration model performance of reflectance to absorbance transformation spectra combined with pre-processing spectra to find the best model to predict white rice flour adulteration in brown rice flour using the visible and near-infrared spectrometer. Partial least squares regression (PLSR) and principal component regression (PCR) were compared using reflectance, Kubelka-Munk (KM), and Log(1/R) spectra. Area normalization (AN) and Savitsky-smoothing Golay's (SGS) were pre-processing methods. The sample was white rice flour mixed with brown rice flour at 0%, 5%, 10%, 15%, 20%, and 25%. Reflectance spectra outperformed KM and log (1/R) spectra in this study. Reflectance spectra provided the best model for PLSR and PCR. Pre-processed SGS spectra were best for PLSR, while raw reflectance spectra were best for PCR. PLSR and PCR both had an R 2 of prediction of 0.96, while the overall average R 2 of prediction favors PLSR over PCR. The present study led to the discovery of a simple novel method for developing adulteration flour and showed that a visible near-infrared spectrometer combined with PLSR, or PCR, could predict white rice flour adulteration in brown rice flour.