Experimental Response Surface Research Articles

Antidiarrheal Effect of Fermented Millet Bran on Diarrhea Induced by Senna Leaf in Mice.

Bacillus natto is a kind of probiotic with various functional characteristics, which can produce a lot of nutrients during growth and reproduction. Bacillus natto was used as strain, the number of viable bacteria and the content of soluble dietary fiber in millet bran were used as indexes to study the effects of inoculum size, fermentation time, and fermentation temperature on the fermentation effect, and the optimal fermentation conditions were determined by a response surface experiment. The antidiarrhea effect of fermented millet bran prepared under the best technological conditions was evaluated. The results showed that the optimum fermentation conditions were as follows: inoculum size was 7.48%, fermentation time was 47.04 h, and fermentation temperature was 36.06 °C. Under the optimal fermentation conditions, the viable bacteria count of millet bran was 8.03 log CFU/mL and the soluble dietary fiber content was 12.14%. The fermented millet bran can significantly reduce the intestinal thrust rate and serum levels of IL-6, IL-12, and TNF-α, and significantly increase the secretion of SIgA in the intestinal mucosa, which can relieve diarrhea induced by senna leaf in mice. The results of this study can provide the scientific basis for deep processing of millet bran and efficient utilization of fermented millet bran, and also provide the theoretical basis for clinical treatment of diarrhea.

Effect of process parameters on the temperature changes during robotic bone drilling.

In medical surgery, bone drilling is an inevitable procedure. The thermal necrosis in the drilling process can affect post-operative recovery. In this study, the method of drill bit precooling is proposed in bone drilling with robot assisted system. The influence of process parameters on the drilling temperature were investigated and analyzed. The results showed that the method of drill bit precooling could reduce the drilling temperature. The drill bit starting temperature and the feed rate were more important parameters on the drilling temperature compared with rotational speed and cooling length of the drill bit. The quadratic regression model obtained from response surface experiments can predicted the drilling temperature correctly under the range of process parameters in this study. The optimal parameter combination is rotational speed = 1610 rpm, feed rate = 0.5 mm/s, the starting temperature of drill bit = 8°C, and the cooling length = 34.8 mm. The results provide an effective method to reduce thermal necrosis of bone cells in drilling.

Bio-based herding and gelling agents from cholesterol powders and suspensions in organic liquids for effective oil spill clean-up

The negative impacts of an oil spill are severe and can last for decades after the incident. The development of techniques to overcome this threat is crucial to the ecosystem as well as human lives. The herder effectiveness of different cholesterol forms, including powders and suspensions, were measured and compared by using a MATLAB code to estimate the surface area of oil spill contracted/thickened. The powders were distinguished by their particle size distributions, crystal phases, and thermal properties. Formation of gel oil aggregates was achieved by all cholesterol powders. The highest herder effectiveness of 73.3 ± 2.0% was shown by CP/D, that is, the cholesterol powder that had the lowest particle sizes of 0.5–0.99 mm, anhydrous crystal phases, and lowest thermal degradation rate of 95.4%. Cholesterol suspensions were further prepared from the mixtures of CP/D and delivery liquids, namely gasoline, toluene, and biodiesel by varying CP/D-to-solvent ratio from 1:2 to 1:4. Herding of oil spill, instead of gel oil aggregation only, was achieved by cholesterol suspensions. Biodiesel was found to be the most efficient delivery liquid, resulting in the highest herder effectiveness of 79.1 ± 0.7%. CP/D-biodiesel suspension reduced the surface tension of water from 73.5 to 28 mN/m. Optimum herder effectiveness was estimated from full factorial experimental design and Response Surface Methodology at different conditions of temperature, water salinity and agent-to-oil ratio (AOR). Analysis of variance (ANOVA) confirmed that salinity and temperature had significant effects on the herder effectiveness of CP/D-biodiesel but the effect of AOR was insignificant. The optimum herder effectiveness was 79.5% and the accuracy of this prediction was obtained as 95%. This study demonstrated that CP/D-biodiesel suspension is a promising bio-based herding agent.

Selective laser melting of CuCrZr alloy: processing optimisation, microstructure and mechanical properties

The effect of process parameters on the densification behaviour and microstructural characteristics of CuCrZr alloy processed by selective laser melting (SLM) was systematically investigated. The effect of laser power and scanning speed on the surface morphology of the samples with single track fabricated by SLM was investigated. Additionally, the bulk samples were produced to investigate the influence of the scanning strategy on the densification level. The coupled model of the effect of process parameters on relative density was established by response surface methodology (RSM) and experiment. The process parameters were optimized to obtain almost fully dense CuCrZr samples with a relative density close to 99.57%. The microstructural analysis demonstrated the presence of stable melt tracks without obvious porosity. The grain morphology and orientation are highly correlated with laser trajectory and construction direction. The samples present obvious cellular and columnar structures. The XRD results show that, apart from the diffraction peaks of α-Cu, the diffraction peaks of other phase components were not detected. Finally, the ultimate tensile strength of 338 MPa, yield strength of 216 Mpa and elongation of 42.4% were achieved for the SLMed CuCrZr parts.

Development of Functional Kiwifruit Jelly with chenpi (FKJ) by 3D Food Printing Technology and Its Anti-Obesity and Antioxidant Potentials.

With the growing popularity of the concept of healthy diet, modern obesity treatment is gradually shifting from surgical or pharmacological treatment to nutritional intervention. As a safe and effective measure, natural product interventions are a potential strategy of obesity management. The present study aimed to develop a kind of functional food rich in bioactive compounds (chenpi, kiwifruit, and pectin as raw materials) and investigate their bioactive effects on a mouse model. For development of functional kiwifruit jelly with chenpi (FKJ), the results of single-factor and response surface experiments showed that the optimized formulation was composed of a 30.26% addition of chenpi, 35% addition of kiwifruit juice, and 2.88% addition of pectin. The FKJ obtained with the optimal formulation could be used as a 3D printing raw material to print the desired food shapes successfully. For bioactivity evaluation of FKJ, the results with a mouse model showed that the food intake, liver weight, and adipose tissue weight were significantly decreased after administration of FKJ with dose-dependent effect compared to the CON group (p < 0.05). Meanwhile, the serum levels of several inflammatory factors (TG, IL-6, and TNF-α) were decreased and the activities of several antioxidant-related enzymes (SOD, GSH-PX, and CAT) were increased. In short, a functional kiwifruit jelly with chenpi was developed in this study. It is a functional snack food rich in active phenolic compounds, low in calories, with antioxidant and anti-inflammatory activity, and prevents fat accumulation. FKJ could well meet the needs of modern people for nutrition and health and also promote the processing and utilization of natural products, and has good development prospects in the functional food industry.

Extraction of High-Purity Native State Gutta-Percha from Enzymatic Hydrolyzed Eucommia ulmoides Pericarps by Ultrasound Treatment and Surfactant Aqueous Phase Dispersion

Herein, a method of ultrasound treatment combined with surfactant aqueous phase dispersion was proposed for the extraction of high-purity gutta-percha in its native state from enzymatic hydrolyzed Eucommia ulmoides pericarps. Firstly, the plant tissues wrapped around gutta-percha were destructed through enzymatic hydrolysis, then the plant tissues debris still attached to gutta-percha were further stripped off by ultrasound. Finally, under the “amphiphilic” action of sodium dodecyl sulfate (SDS), the entangled gutta-percha was untwined, allowing the residual plant tissue debris to be released and precipitated, thus high purity gutta-percha was obtained. The process parameters were optimized through single factor and response surface experiments. The optimal parameters for ultrasonic treatment were displayed as follows: frequency of 40 kHz, power of 320 W, time of 7.3 h, temperature of 50 °C, and material-to-liquid ratio of 1:70 g/mL, and for the aqueous phase dispersion of surfactant were SDS concentration 1.7%, temperature 80 °C, stirring speed 1200 rpm, solid-to-liquid ratio 1:60 g/mL, and time 60 h. Under optimal conditions, the purity of gutta-percha reached 95.4 ± 0.31% and its weight average molecular weight (Mw) was 20.85 × 104. Moreover, the obtained gutta-percha maintained its native filamentous form. The obtained products were characterized by IR, NMR, XRD, TGA, DSC, and tensile experiments, which showed that the obtained product was gutta-percha and maintained the natural α- and β- crystal structure. The proposed method overcomes the disadvantages of the traditional organic solvent method, which has great environmental pollution and destroys the gutta-percha structure. This is also the first reported method to obtain high purity gutta-percha while maintaining its native state.

Dye removal with emulsion liquid membrane: experimental design and response surface methodology

ABSTRACT This work aims to removing anionic food dyes, Acid Red18 (E124) and Quinoline Yellow WS (E104), from their aqueous solutions. The Emulsion Liquid Membrane (ELM) technique was used. ELM consists of diluent (kerosene), nonionic surfactant (0.5 wt. % Triton X-45), Aliquat 336 as an extractant. Sulfuric acid (H2SO4) solution was used as an internal aqueous phase. The key parameters impacting the stability of liquid membrane and the efficiency of dye removal were investigated; Almost 98% of E124 at 50 mg/L are successfully extracted under optimum conditions. The extraction of a mixture of the two dyes at equal concentrations (25 mg/L) was conducted and their extraction showed more than 95% of efficiency. The experimental results of dye mixture (E124, E104) extraction were expressed by the following three quantities: The concentration of Triton X-45, the concentration of Aliquat 336, and the internal phase concentration of H2SO4, represented on three dimensional plots using the Box-Behnken design and the response surface methodology. For each of the parameters, the values of which were determined by experimental design, these results were subjected to empirical smoothing. The values, thus calculated, are consistent with the measurements.

Mapping and optimization of an industrial steam methane reformer by the design of experiments (DOE)

Natural gas is an important precursor to produce synthesis gas through the steam reforming process. This work aims to map the optimal operating conditions of a steam methane reformer based on the design of experiments (DOE) approach and response surface methodology (RSM) relying on a phenomenological model validated with industrial data. A screening factorial design 2IV8−4is initially conducted to identify the most significant process variables, followed by a 25 full factorial design for a more accurate analysis of the main and interaction effects of the input variables on the methane conversion and syngas quality. The most significant variables are the steam to carbon ratio, the flow rate of the stream fed to the reforming tubes, and feed gas and combustion air temperatures. A Box-Behnken design (BBD) with 25 experiments is carried out and polynomial models are proposed and validated through the analysis of variance with great confidence. An optimization problem is formulated to maximize the methane conversion, ensure the quality, and tube wall temperature constraints. This problem is solved in Excel, using the generalized reduced gradients method and the calculated optimal point is analyzed through contour plots.

Performance and cost analysis of dye wastewater treatment by Fenton, electro-Fenton, and biosorption: Box-Behnken experimental design and response surface methodology

Performance and cost analysis of dye wastewater treatment by Fenton, electro-Fenton, and biosorption: Box-Behnken experimental design and response surface methodology

Crankshaft Optimization Based on Experimental Design and Response Surface Method

To improve the applicable performance of the engine and accomplish the determination of optimization, the crankshaft, as one of its essential components, is optimized based on experimental design and response surface method (RSM). First, the static analysis of the crankshaft is carried out. Over the solution, the maximum equivalent stress and deformation distribution of the crankshaft and the area with the most concentrated stress are obtained to provide the direction for subsequent optimization. Then the modal analysis is carried out to define the portions with large amplitude to prevent resonance. At the same time, based on the modal analysis results, the harmonic response of the crankshaft is examined to ensure that the crankshaft can avoid resonance and fatigue caused by forced vibration at different engine speeds. It also provides a theoretical basis for the further optimization design of the crankshaft. Then, through the experimental design and response surface optimization analysis, the optimization purpose of reducing the maximum equivalent stress, maximum deformation, and lightweight of the crankshaft is accomplished. Through the design expert software, the response surface model and fitting equation of the crankshaft are solved by the RSM, which provides a reference basis for optimizing the crankshaft. Finally, according to the optimization scheme, the crankshaft is reconstructed, and the optimized crankshaft model is compared with the original model. After optimization, the maximum equivalent stress is reduced by 9.43%, the maximum deformation is reduced by 3.68%, and the mass is reduced by 1.30%. At the same time, the first three natural frequencies are reduced by 10.28, 10.28, and 10.34%, which achieves the purpose of optimizing the crankshaft design. The research results provide effective theory and evidence for the structural design of the crankshaft.

Experimental design for estimating the power potential of the Wairakei geothermal field, New Zealand: A retrospective analysis

Uncertainty quantification of power (MWe) prediction from a geothermal numerical model is time-consuming. Existing techniques and workflows are still being tested. Our study focuses on using the Experimental Design (ED) and Response Surface Methodology (RSM) framework as an alternative method to facilitate probabilistic MWe estimation. This study involves two types of Experimental Design: the two-level Full Factorial and Plackett Burman, and the investigation is divided into two parts. The first part investigated the difference in the prediction of the Wairakei geothermal field power potential using the polynomial model built from the 64 simulation runs based on the two-level Full Factorial design and the 12 simulation runs based on the Plackett-Burman configuration. The second section compared the MWe predictions using the Plackett-Burman design and the volumetric stored heat method. The simulated MWe potential of Wairakei for 50 years is comparable for both the two-level Full Factorial and Plackett-Burman designs, indicating the latter as a practical design for building a proxy model of a numerical model. Furthermore, the MWe prediction of the polynomial model created based on the ED Framework closely resembles the actual production capacity of Wairakei compared to the volumetric stored heat method. The results based on the proxy modelling further indicate that the 353 MWe production generation could be sustainable at least for another 40 years.

Extraction of Phenolic Compounds from Coleus amboinicus Leaves by Microwave-assisted Extraction: Optimization of the Operating Condition

Torbangun (Coleus amboinicus L) leaf is one of the herbs from Indonesia that has been reported to have many bioactive compounds for human health. These phytochemicals are predominantly incorporated into phenolics, such as flavonoids. An extraction process is needed to obtain all the valuable compounds, and conventional solvent extraction, such as heating and maceration, could be easily applied because of its simplicity. However, this method requires high energy, a longer extraction time, and a large amount of solvent. To overcome these limitations, in this study, microwave-assisted extraction (MAE) was utilized to extract phenolic compounds, including flavonoids from torbangun leaves. Three factors (solvent to feed ratio, microwave power, and extraction time) were evaluated to affect the three responses (extract volume, TPC, and TFC). The extraction process optimization was carried out to get a higher response. The Box-Behnken experiment design and Response Surface Methodology (RSM) determined the optimal operating condition. The result shows 30 ml/g of solvent to feed ratio, 300 W of microwave power, and 4.6 minutes of extraction time as the optimum condition. Applying those conditions, the extract is expected to reach 10.13 ml of extract volume, 9.17 mg GAE/ ml extract of total phenolic, and 3.62 mg QE/ ml extract of total flavonoid. In sum, MAE was useful for extracting phenolic compounds from torbangun leaves and could be an alternative method due to its high efficiency.

Probabilistic geothermal resource assessment using experimental design and response surface methodology: The Leyte geothermal production field

Estimating power potential (MWe) with higher accuracy remains a necessity and a challenge confronting the geothermal industry. Reservoir models can predict MWe capacity probabilistically for resource management and decision-making use, but the process remains laborious to implement. This work involves applying the Experimental Design (ED) and Response Surface Methodology (RSM) framework to a calibrated natural-state reservoir model for predicting MWe probabilistically, quantifying uncertainties in the prediction and identifying the key driving factors.This study has chosen six uncertain parameters and implemented the Plackett-Burman design to build twelve versions of the Leyte reservoir model for uncertainty quantification. These uncertain parameters are permeability in the x, y and z-direction, porosity, reinjection enthalpy (RI Enthalpy), and the fraction of reinjection (% RI). Results revealed that all of these parameters except RI Enthalpy are significant predictors of MWe and that the Leyte Geothermal Production Field (LGPF) has an indicative capacity of 670 MWe (P90), 730 MWe (P50) and 790 MWe (P10) if it operates for 50 years.

Modeling and optimization of flexural properties of FDM-processed PET-G specimens using RSM and GWO algorithm

As in every manufacturing process, fused deposition modeling (FDM) is strongly related to its operational parameters. 3D-printed components are anisotropic and brittle and this imposes the need to investigate the effect of FDM-related parameters to improve functionality and strength. In this paper the flexural strength of polyethylene terephthalate glycol (PET-G) is studied by testing different levels for five important process-related parameters; the height of each layer, density of infill, angle of deposited material, printing speed and printing temperature. A response surface experiment with 27 runs was conducted to obtain results for flexural strength (MPa) and proceed with the examination of the effect of each parameter on the response using statistical analysis. The experiments were performed according to ASTM D790 standard. Experimental observations dealing with fructure mechanics and failure modes were recorded and analysed. Based on the analysis of variance (ANOVA) a full quadratic regression equation was generated and verified for its efficiency. Finally the model was implemented as an objective function for a modern population-based algorithm known as grey wolf algorithm (GWO). It was shown that the algorithm can suggest good combination for parameter settings to maintain good flexural strength with a gain close to 15% compared to the highest value obtained by the series of experiments conducted.

One-Step Synthesis of Cross-Linked Esterified Starch and Its Properties

Cross-linked esterified starch (CES) was prepared using a one-step method, where maize starch was selected as the raw material, sodium trimetaphosphate as the cross-linking agent, and acetic anhydride as the esterifying agent, respectively. A response surface experiment was systematically conducted for analyzing the correlation of the experimental variables (cross-linked temperature, pH, reaction time, sodium trimetaphosphate and acetic anhydride dosage) and properties of the product (peak and final viscosity). The Brabender viscosity, freeze-thaw stability, shearing resistance, and acid tolerance of the cross-linked acetylated dual modified starch were studied under different conditions of crosslinking degree and acetyl content. Meanwhile, the granular structure and morphology of the modified starch were analyzed. The results indicated that: after cross-linked acetylated dual modification, the starch had a distinct birefringence and granular structure, along with the creation of new carbonyl groups. The low degree of crosslinking and high acetyl contents were beneficial to the viscosity, which was significantly increased at both low and high temperatures. Moreover, the freeze-thaw stability of CES was elevated sharply after five cycles. In addition, CES displayed increased shear and acid tolerance compared to the original waxy maize, and their lowest differences between waxy maize and CES were only 0.62% and 0.59%, respectively. In summary, a novel method for starch modification was provided, and the synthesized CES was suggested to have exceptional performance for the food industry.

Preparation, Characterization, and Cytoprotective Effects on HUVECs of Fourteen Novel Angiotensin-I-Converting Enzyme Inhibitory Peptides From Protein Hydrolysate of Tuna Processing By-Products.

To effectively utilize skipjack tuna (Katsuwonus pelamis) processing by-products to prepare peptides with high angiotensin-I-converting enzyme (ACE) inhibitory (ACEi) activity, Neutrase was selected from five kinds of protease for hydrolyzing skipjack tuna dark muscle, and its best hydrolysis conditions were optimized as enzyme dose of 1.6%, pH 6.7, and temperature of 50°C using single factor and response surface experiments. Subsequently, 14 novel ACEi peptides were prepared from the high ACEi protein hydrolysate and identified as TE, AG, MWN, MEKS, VK, MQR, MKKS, VKRT, IPK, YNY, LPRS, FEK, IRR, and WERGE. MWN, MEKS, MKKS, and LPRS displayed significantly ACEi activity with IC50 values of 0.328 ± 0.035, 0.527 ± 0.030, 0.269 ± 0.006, and 0.495 ± 0.024 mg/mL, respectively. Furthermore, LPRS showed the highest increasing ability on nitric oxide (NO) production among four ACEi peptides combining the direct increase and reversing the negative influence of norepinephrine (NE), and MKKS showed the highest ability on directly decreasing and reversing the side effects of NE on the secretion level of endothelin-1 (ET-1) among four ACEi peptides. These findings demonstrate that seafood by-product proteins are potential ACEi peptide sources and prepared ACEi peptides from skipjack tuna dark muscle, which are beneficial components for functional food against hypertension and cardiovascular diseases.

Titanium alloy piston thermo-mechanical coupling simulation and multi-objective optimization design

To solve the problem between temperature and thermal stress of a titanium alloy piston, a multi-objective optimization method combined response surface methodology and experiment design is performed to calculate an optimal design of the titanium alloy piston. Firstly, the thermo-mechanical coupling analysis, static and dynamic characteristics analysis are carried out. The analysis results show that the thermal load has a significant influence on the piston. Secondly, the five dimensional parameters are chose as the design variables through sensitivity analysis. The piston thermo-mechanical coupling stress, deformation, mass, and the first ring groove are selected as the objective functions. By using the optimal space-filling design method, the sample points between design variables and objective functions are gained. Then, the mathematical relationship between them is obtained by the response surface method. Finally, the multi-objective genetic algorithm is employed to optimize the mathematical model. After optimization, the maximum coupling deformation decreases by 3.05%, the maximum coupling stress decreases by 27.85%, the mass reduces by 5.46%. The maximum temperature of the first ring groove reduces by 12.54%. This study can provide a reference for the piston optimization design.

Experimental study on wax removal and viscosity reduction of waxy crude oil by Ochrobactrumintermedium

To investigate the influence of microbial wax removal and viscosity reduction technologies on the fluidity of waxy crude oil, this study took the waxy crude oil from China's Daqing Oilfield as the experimental object for microbial wax removal and viscosity reduction experiment. First, utilizing standard strain screening and culture protocols, a high-efficiency microbial strain H-1 (Ochrobactrum intermedium) was proposed from in situ soil. The single factor experiment and multi-factor response surface analysis were then utilized to optimize the temperature, initial pH value of the medium, and NaCl mass concentration needed for the strain's growth. Oil displaced activity and emulsification tests were used to evaluate the biosurfactants produced by the metabolism of strain H-1, and Fourier transform infrared spectroscopy was used to identify the types of biosurfactants. Finally, the application effect of strain H-1 on wax removal and viscosity reduction of waxy crude oil were clarified through the wax crystal morphology, wax content, and viscosity of waxy crude oil. The research findings indicated that strain H-1 produced best at a temperature of 38.5 °C, pH value was 7.1 and the mass fraction of NaCl was 0.64%. The lipopeptide biosurfactant produced by strain H-1 can displace oil. Additionally, strain H-1 has a high emulsifying capacity, with a 61.25% emulsifying coefficient. After 7 days of treatment with the strain H-1, the wax crystal morphology of the waxy crude oil changed from a large-sized aggregated to a small-sized sparse condition, and the wax content of the waxy crude oil fell by 38.67%. The viscosity reduction rate of strain H-1 to waxy crude oil was consistently greater than 30% over the temperature range of 30–42 °C, with the greatest rate of 42.38% at 39 °C. The preceding results demonstrate that strain H-1 can degrade the wax components of waxy crude oil, lower the crude oil's low temperature viscosity, and then improve the crude oil's low-temperature fluidity.

Experimental investigation on mechanical behavior of fiber–metal laminates reinforced by hybrid carbon nanotubes and nanosilica under quasi-static pressure load

In this study, the effect of carbon nanotubes (CNT) and silica nanoparticles on quasi-static behavior of fiber–metal laminates (FML) has been experimentally scrutinized. FML consists of two layers of aluminum alloy plates and four composite layers including CNT/nanosilica-reinforced epoxy resin and glass fibers. The effect of weight percentage of carbon nanotube and nanosilica incorporated and their weight ratio in resin epoxy on the performance of FMLs against quasi-static compressive load has been considered. Furthermore, the design of experiments method and response surface methodology have been put into practice to develop an accurate mathematical relationship between the input parameters and the response variable. After designing and performing the experiments based on analysis of variance, a mathematical model corresponding to the real process is obtained. Moreover, the presented model has been validated by statistical methods. The results of this study indicate that the energy absorption capacity of these materials significantly increase through adding CNT to the FML, the highest failure force of 11.64 kN was obtained for FLMs comprising 0.6 wt.% of CNT and 3 wt.% of SiO2. An improvement of 27.88% and 45.86% in the absorbed energy and failure force was achieved, respectively, by adding 3 wt.% of SiO2 and 0.6 wt.% of CNT to FLM compared to pristine FLM.

Drying characteristics and quality optimization of papaya crisp slices based on microwave vacuum drying

In order to improve the drying quality and obtain a crispy texture of papaya slices, microwave vacuum drying (MVD) was studied in this research. The effects of different slice thickness (3, 6, 9, 12 mm), microwave power density (6, 8, 10, 12 W/g), drying temperature (50, 55, 60, 65, 70°C), and vacuum degree in relative pressure (−75, −80, −85, −90 kPa) on the drying characteristics and comprehensive quality of papaya slice were discussed. The Box–Behnken central combination experiments were designed and the response surface optimization analysis was carried out. According to the results of the response surface experiments, the impact factors during papaya slices drying on the comprehensive score were ranked from largest to smallest as follows: microwave power density, vacuum degree, and drying temperature. The fragility and hardness of papaya slices showed an upward trend with the increase of thickness. The optimum technologic parameters were set at the microwave power density of 10 W/g, vacuum degree of −90 kPa, drying temperature of 54.58°C, and slice thickness of 6 mm. The comprehensive score F can be up to the maximum value of 8.80 with the deviation from the verification test of 4.4%, and the papaya slices with obvious pore structure and remarkable crispness were obtained. Novelty impact statement Microwave vacuum drying technology combines the advantages of microwave drying and vacuum drying, which has remarkable drying efficiency through internal heating and promotes the slices to form a crispy texture. In this work, the influence of different factors on the fragility and hardness quality of papaya chips were explored firstly. Increasing drying temperature has no significant influence on the fragility and hardness value. Meanwhile, the hardness value went up while the fragility fluctuated slightly as the power density was added. The variation trend of papaya porosity microstructure gradually expanded with the increase of vacuum degree. The results provided theoretical support for the application of microwave vacuum drying technology in papaya crisp chips.