PENDUGAAN UMUR SIMPAN TERHADAP PRODUK BUMBU NASI KUNING DENGAN METODE ASLT (Accelerated Shelf-Life Testing) MODEL ARRHENIUS

The purpose of this research is to study the shelf life of Yellow Rice Seasoning by the method of ASLT (Accelerated Shelf Life Testing) – Arrhenius Model. The preliminary research was done by determining the best formulation between three formulations, which are seasoning with coconut milk ingredient, seasoning with nutmeg ingredient, and seasoning without neither coconut milk nor nutmeg. The main research is purposed to determine the influence of temperature (25°C, 35°C and 45°C) to the quality of Yellow Rice Seasoning which is stored for 35 days with 5 days time span observation. The responses in this research are chemical responses (TBA value and Iod value), and microbiological response (total microbia). The result of preliminary research showed that the best formulation which liked the most by consument was the yellow rice seasoning with coconut milk ingredient. The result of main research showed that the prediction of yellow rice seasoning shelf life by TBA value in temperature 25°C, 35°C and 45°Cconsecutively is 150,93 days, 112,87 days, and 82,43 days. The prediction of yellow rice seasoning shelf life by Iod value in temperature 25°C, 35°C and 45°Cconsecutively is 0,953 days, 0,672 days, and 0,476 days. The prediction of yellow rice seasoning shelf life by total microbia in temperature 25°C, 35°C and 45°Cconsecutively is 26,00 days, 24,52 days, and 19,87 days. The prediction of yellow rice seasoning shelf life by organoleptical test is 35 days. Based on the result of this research, it could be concluded that the higher the storage temperature, the shorter the shelf life. The response which could be used for determining the shelf life by the model of Arrhenius for yellow rice seasoning is total microbia. The result by total microbia is the closest one to the result of organoleptical test

PENDUGAAN UMUR SIMPAN SERBUK PERWARNA ALAMI DARI KULIT BUAH NAGA (Hylocereus polyrhizus) DENGAN METODE

Tujuan penelitian adalah agar limbah dari kulit buah naga merah dapat dimanfaatkan sebagai serbuk pewarna dan mendapatkan umur simpan dari produk menggunakan metode Arrhenius. Penelitian terdiri dari penelitian pendahuluan bertujuan untuk mengetahui intensitas warna, kadar air, dan kelarutan pada serbuk pewarna alami dari kulit buah naga merah. Penelitian utama bertujuan untuk mengetahui umur simpan dari kulit buah naga merah akibat suhu penyimpanan 25°C, 35°C dan 45°C terhadap kualitas serbuk pewarna alami dari kulit buah naga merah. Berdasarkan hasil penelitian dapat disimpulkan bahwa umur simpan serbuk pewarna alami dari kulit buah naga merah yang dikemas dalam kemasan plastik metalize berdasarkan perubahan warna yaitu pada suhu 25°C adalah 20 hari, 35°C adalah 18 hari, dan 45°C adalah 17 hari, sedangkan berdasarkan kadar air yaitu pada suhu 25°C adalah 49 hari, 35°C adalah 46 hari, dan 45°C adalah 43 hari, dan berdasarkan nilai kelarutan yaitu pada suhu 25°C adalah 150 hari, 35°C adalah 133 hari, dan 45°C adalah 119 hari. Kata kunci: buah naga merah, pewarna, umur simpan

Temporal Asynchrony but Not Total Energy Nor Duration Improves the Judgment of Numerosity in Electrotactile Stimulation

Stroke patients suffer from impairments of both motor and somatosensory functions. The functional recovery of upper extremities is one of the primary goals of rehabilitation programs. Additional somatosensory deficits limit sensorimotor function and significantly affect its recovery after the neuromotor injury. Sensory substitution systems, providing tactile feedback, might facilitate manipulation capability, and improve patient's dexterity during grasping movements. As a first step toward this aim, we evaluated the ability of healthy subjects in exploiting electrotactile feedback on the shoulder to determine the number of perceived stimuli in numerosity judgment tasks. During the experiment, we compared four different stimulation patterns (two simultaneous: short and long, intermittent and sequential) differing in total duration, total energy, or temporal synchrony. The experiment confirmed that the subject ability to enumerate electrotactile stimuli decreased with increasing the number of active electrodes. Furthermore, we found that, in electrotactile stimulation, the temporal coding schemes, and not total energy or duration modulated the accuracy in numerosity judgment. More precisely, the sequential condition resulted in significantly better numerosity discrimination than intermittent and simultaneous stimulation. These findings, together with the fact that the shoulder appeared to be a feasible stimulation site to communicate tactile information via electrotactile feedback, can serve as a guide to deliver tactile feedback to proximal areas in stroke survivors who lack sensory integrity in distal areas of their affected arm, but retain motor skills

A system for electrotactile feedback using electronic skin and flexible matrix electrodes: Experimental evaluation

Myoelectric prostheses are successfully controlled using muscle electrical activity, thereby restoring lost motor functions. However, the somatosensory feedback from the prosthesis to the user is still missing. The sensory substitution methods described in the literature comprise mostly simple position and force sensors combined with discrete stimulation units. The present study describes a novel system for sophisticated electrotactile feedback integrating advanced distributed sensing (electronic skin) and stimulation (matrix electrodes). The system was tested in eight healthy subjects who were asked to recognize the shape, trajectory, and direction of a set of dynamic movement patterns (single lines, geometrical objects, letters) presented on the electronic skin. The experiments demonstrated that the system successfully translated the mechanical interaction into the moving electrotactile profiles, which the subjects could recognize with a good performance (shape recognition: 86±8% lines, 73±13% geometries, 72±12% letters). In particular, the subjects could identify the movement direction with a high confidence. These results are in accordance with previous studies investigating the recognition of moving stimuli in human subjects. This is an important development towards closed-loop prostheses providing comprehensive and sophisticated tactile feedback to the user, facilitating the control and the embodiment of the artificial device into the user body scheme

Multichannel electrotactile feedback with spatial and mixed coding for closed-loop control of grasping force in hand prostheses

Providing somatosensory feedback to the user of a myoelectric prosthesis is an important goal since it can improve the utility as well as facilitate the embodiment of the assistive system. Most often, the grasping force was selected as the feedback variable and communicated through one or more individual single channel stimulation units (e.g., electrodes, vibration motors). In the present study, an integrated, compact, multichannel solution comprising an array electrode and a programmable stimulator was presented. Two co ding schemes (15 levels), spatial and mixed (spatial and frequency) modulation, were tested in able-bodied subjects, psychometrically and in force control with routine grasping and force tracking using real and simulated prosthesis. The results demonstrated that mixed and spatial coding, although substantially different in psychometric tests, resulted in a similar performance during both force control tasks. Furthermore, the ideal, visual feedback was not better than the tactile feedback in routine grasping. To explain the observed results, a conceptual model was proposed emphasizing that the performance depends on multiple factors, including feedback uncertainty, nature of the task and the reliability of the feedforward control. The study outcomes, specific conclusions and the general model, are relevant for the design of closed-loop myoelectric prostheses utilizing tactile feedback

A hierarchical sensorimotor control framework for human-in-the-loop robotic hands.

Human manual dexterity relies critically on touch. Robotic and prosthetic hands are much less dexterous and make little use of the many tactile sensors available. We propose a framework modeled on the hierarchical sensorimotor controllers of the nervous system to link sensing to action in human-in-the-loop, haptically enabled, artificial hands

A Novel Method for Vibrotactile Proprioceptive Feedback Using Spatial Encoding and Gaussian Interpolation

Objective: The bidirectional communication between the user and the prosthesis is an important requirement when developing prosthetic hands. Proprioceptive feedback is fundamental to perceiving prosthesis movement without the need for constant visual attention. We propose a novel solution to encode wrist rotation using a vibromotor array and Gaussian interpolation of vibration intensity. The approach generates tactile sensation that smoothly rotates around the forearm congruently with prosthetic wrist rotation. The performance of this scheme was systematically assessed for a range of parameter values (number of motors and Gaussian standard deviation). Methods: Fifteen able-bodied subjects and one individual with congenital limb deficiency used vibrational feedback to control the virtual hand in the target-achievement test. Performance was assessed by end-point error and efficiency as well as subjective impressions. Results: The results showed a preference for smooth feedback and a higher number of motors (8 and 6 versus 4). With 8 and 6 motors, the standard deviation, determining the sensation spread and continuity, could be modulated through a broad range of values (0.1 - 2) without a significant performance loss (error: ∼ 10%; efficiency: ∼ 30%). For low values of standard deviation (0.1-0.5), the number of motors could be reduced to 4 without a significant performance decrease. Conclusion: The study demonstrated that the developed strategy provided meaningful rotation feedback. Moreover, the Gaussian standard deviation can be used as an independent parameter to encode an additional feedback variable. Significance: The proposed method is a flexible and effective approach to providing proprioceptive feedback while adjusting the trade-off between sensation quality and the number of vibromotors