Rice Milling Process Research Articles

Adsorption Studies of Rice Husk-Based Silica/Carbon Composite

Rice husk as a by-product of the rice milling process is a material that can still be processed to be a product that can be used in various applications. The potential for the commercialization ofrice husks is still hampered by its low economic value. By using the heating method using an inert gas, rice husk can be converted into a composite which contains mostly silica and carbon, a wellknown component with excellent adsorbent properties. This aimed to study the preparation of rice husk-baased silica/carbon composite and its adsorption behavior. In this research, the utilization of rice husk into silica/carbon composites was done by using three different methods. Common heating under temperature of 800 oC, heating process under temperature of 800 oC using furnace equipped with inert gas, and heating process under temperature of 800 oC using furnace equipped with inert gas with addition of glucose solution were carried out in order to obtain three different kinds of composite. Analysis and characterization using were performed to observe the properties of the composites. As the result, from Fourier Transform Infra-Red and X-Ray diffraction characterizations, silica/carbon composites were successfully made as both of carbon and amorphous silica spectra appeared in the result. Furthermore, composite made under temperature of 800 oC using furnace equipped with inert gas with addition of glucose solution has the highest adsorption capacity and Langmuir’s model adsorptive behavior with R2 value of 0.935.

Rice Bran Protein Powder Production Using Spray Drying Technique: Effect of Temperature, Feed Flowrate and Air Flowrate

.Rice bran is quite a novel subject in the food and pharmaceutical research area. It is the by-product of the rice milling process that is rich in proteins and many other nutrients. However, rice bran is commonly used to feed cattle, also as fertilizer and fuel but not as a source of nutrients for humans. Thus, this study proposes another protein source and explore its production methods for food and supplement industry. This research focuses to produce rice bran protein powder and protein concentration using spray drying technique. Since rice bran protein is used in food consumption, the extraction of protein from rice bran was done using physical extraction method which water as the medium of extraction. The relationship between the spray drying parameter; inlet temperature (130 – 200˚C), feed flowrate (10 – 40%) and air flowrate (225 – 625L/Hr) were investigated based on the OFAT method, As conclusion, spray drying process of rice bran protein powder has the capability to maintain the nutritional value present in the rice bran. Rice bran protein powder could be an alternative source of hypoallergenic plant-based protein supplement to humans in the future with further research.

The phytochemical analysis and pharmacological potentials of husk and straw as paddy waste products.

Rice serves as a staple food for one-half of the global population. However, rice production, particularly the rice milling process, results in a substantial amount of paddy waste products (e.g. bran, husk and straw) annually. Because the potentials of bran have been extensively explored in prior studies, the present review focuses exclusively on the phytochemical analysis and pharmacological potentials of husk and straw. This comprehensive review establishes a solid foundation for promoting husk and straw as medicinal substances given their promising pharmacological potentials as bioactive compound sources with therapeutic functions. © 2020 Society of Chemical Industry.

Physicochemical and functional properties of medium‐sized broken rice kernels and their potential in instant rice production

AbstractBackground and objectivesMedium‐sized broken rice (brokens) is the most abundant fraction of brokens from the rice milling process. This research seeks to determine the physicochemical and functional properties of medium‐sized broken rice, their potential in instant rice production, and effects of aging on the properties. Medium‐sized brokens from rough rice (XL753) dried at three different drying temperatures (25, 45, and 60°C) were stored for 6 months at 0 and 25°C representing nonaged and aged samples, respectively. Instant rice was produced by cooking and drying the brokens after storage. The physicochemical and functional properties of raw (noninstantized) and instantized rice from the brokens were determined.FindingsRice aging had significant impacts on pasting properties of raw medium‐sized brokens. Aged samples had consistently higher trough viscosity, final viscosity, setback viscosity, and pasting temperature than nonaged samples across all drying temperatures. Aging status had a significant impact on whiteness index and oil absorption capacity of brokens. There was no significant effect of aging on protein content, bulk density, water absorption capacity, and emulsification capacity of raw brokens. Rehydrated instant nonaged medium‐sized brokens were harder, more adhesive, cohesive, gummy, chewy, and resilient than rehydrated instant aged samples. The textural profile of rehydrated instant aged broken rice is consistent with the textural properties of cooked rice reported in the literature by other researchers, indicating the feasibility of instant rice production from brokens.ConclusionsThe use of brokens for the production of instant rice is feasible and can reduce the cost of raw materials and improve upon cooked rice sensory characteristic. It is recommended that consumer sensory studies be conducted to determine product acceptability.Significance and noveltyThe study provides information on the enhancement of the value of broken rice as a commodity by accessing novel applications. It also provides science‐based information on the characteristics of medium‐sized broken rice, which is useful in new product development.

Rice bran supplementation improves glucose tolerance and innate immunity in high‐fat diet induced obese ovariectomized mice

ObjectivesMenopause is a state of low estrogen production which is associated with chronic low‐grade inflammation and higher incidence of overweight. Rice bran (RB) is a nutrient‐dense product of rice milling process that is considered a health improving supplement. The aim of this study was to investigate the influences of RB on the innate immunity of high‐fat diet induce ovariectomized (OVX) obese mice.Methods8 months‐old female mice were randomly divided into OVX sham (SH) group and OVX group. After surgery for one week, mice were randomly assigned to one of the three groups (n=12) and fed the respective diet for four months : SH group and OVX‐control (ONC) group were provided with AIN‐95 control diet containing 10% energy as fat, OVX‐high fat diet (OHF) group was treated with high fat diet (HFD) containing 40% fat, mice in the OVX‐high fat diet with RB (OHFR) group were fed with HFD containing RB (10% wt/wt).ResultsMice in the OHF group showed significantly higher body weight gained, plasma glucose and triglyceride levels than those in the SH and other OVX groups. Compare to the SH and ONC groups, the OHF group had lower splenic natural killer (NK) cells cytotoxic capacity and peripheral blood phagocytes phagocytic ability. The chemotactic ability of leukocytes were also lower in the OHF group. As regard to the OVX group with high‐fat diet, RB supplementation increased NK cells cytotoxic function and phagocytosis ability of phagocytes. Also, the chemotactic ability of neutrophils and macrophage as measured by migration speed and directional persistence were improved in the OHFR group.ConclusionThe findings of this study suggest that RB supplementation improved glucose tolerance and prevented the decline of innate immunity in high‐fat diet induced obese mice with OVX.Support or Funding InformationThis study was supported by research grant MOST 107‐2320‐B‐038‐014 from the Ministry of Science and Technology (Taipei, Taiwan).

Extrusion cooking of immature rice grain: under-utilized by-product of rice milling process.

Immature rice grain is one of the by-products of paddy milling process. Due to being "whole grain", immature rice grains comprise the fat-rich bran layer which bring along high nutritional value as well as susceptibility to rancidity. Therefore, they are generally used as "feed" rather than "food". In this study, the potential of utilizing immature rice grain as a food ingredient was investigated. For this purpose, raw (unprocessed) and infrared (IR) stabilized immature rice grain flours (IRGF) were extruded at different exit-die temperatures (130°C and 150°C) and feed moisture contents (16%, 18%, 20%) and the effects of these parameters on chemical composition (moisture, crude fat, protein, ash, soluble and insoluble dietary fiber and phytic acid contents), physicochemical properties (solubility, water binding capacity, expansion index and bulk density), thiamine, riboflavin and tocopherol contents, textural and sensorial properties of the extrudates were investigated. Either thiamine or tocopherol contents of the extrudates made of unprocessed IRGF were higher than that of the extrudates made of IR stabilized IRGF (p < 0.05). Additionally, higher extrusion temperature and lower feed moisture content resulted in further loss in both vitamins. On the other side, riboflavins showed a relatively heat-stable behavior. Rancid flavor and bitter taste scores of the extrudates which were made of unprocessed IRGF were significantly higher than their counterparts made of IR stabilized IRGF (p < 0.05). Toothpack was the most dominant sensory attribute in all extrudates.

Utilization of rice husk (Oryza sativa) for amorphous biosilica (SiO2) production as a bacterial attachment

Rice husk as a by-product of the rice milling process has not been utilized optimally. The yield of rice husk waste continues to increase from year to year, considering that Indonesia is the third largest rice producer in the world. Rice husk has a fairly large silica content; therefore, rice husk is widely used as an alternative source of silica. The purpose of this study is to synthesize silica from rice husk and analyse its characteristics. The research method used in silica isolation was carried out by non-thermal and thermal methods. Non-thermal method for removal of inorganic compounds and hydrolysis of organic compounds by acidic solutions (HCl), while the thermal method is carried out by burning rice husks at a temperature of 500 °C to produce rice husk ash. The resulting rice husk ash was processed by the sol-gel method. The resulting silica was determined of its morphology by Scanning Electron Microscopy (SEM), composition, and structure with Fourier Transform Infrared Spectroscopy (FT-IR). The results obtained in this study were white silica with a yield of 84.782%. Biosilica produced is then mixed with certain bacteria, either Serratia sp or Bacilus pumilus. Then, the attachment of bacteria was evaluated by using SEM (Scanning Electron Microscopy).

Comparison of Antioxidant Activity and Total Lactic Acid Bacteria (LAB) of Goat Milk Yoghurt, Goat Milk Yoghurt Fortified by Redand Black Rice Bran Flour

Yoghurt is a functional food which has various health benefit. Goat milk yoghurt contains bioactive peptides which have the potential as antioxidants. Rice bran, a by-product of rice milling process, is recently popular as animal feed. Rice bran provides good nutritional values and high bioactive compounds, such as antioxidant activity. The objective of this study was to determine the comparison of antioxidant activity and total Lactic Acid Bacteria (LAB) between goat milk yoghurt and goat milk yoghurt fortifiedby red and black rice bran flour. This was a true experimental study with randomization three factor treatments and five repetitions: (1) goat milk yoghurt without red or black rice bran flour fortification; (2) goat milk yoghurt with 4% red rice bran flour fortification; and (3) goat milk yoghurt with 4% black rice bran flour fortification. Yoghurt used in this experiment was a fermented milk product from Lactobacillusbulgaricus, Streptococcus thermophilus, and Lactobacillus acidophilus. Analysis of the total LAB used Total Plate Count (TPC) test and analysis of the antioxidant activity used 2,2-diphenyl-1-picrylhydrazyl (DPPH) test. Data were analysed by Ms. Excell 2010. The addition of red and black rice bran flour to goat milk which were fermented together into yoghurt, has proven to increase antioxidant activity and total LAB, with the highest antioxidant activity and total LAB was the addition of black rice bran flour.

Stabilization treatment of rice bran alters phenolic content and antioxidant activity

AbstractBackground and objectivesRice bran (RB), a by‐product of the rice milling process, is known to be a rich source of bioactive phytochemicals. This study aimed to evaluate the influence of RB stabilization treatments, usually applied to inhibit rancidification, on its phenolic composition and antioxidant activity.FindingsTotal phenolic content (TPC) and antioxidant assays were performed on RB that was exposed to extrusion, drum‐drying, microwave, and oven stabilization treatments. Chemical profiling was conducted using ultra‐high performance liquid chromatography (uHPLC) coupled to an online ABTS system, and liquid chromatography quadrupole time‐of‐flight mass spectrometry (LC‐QTOF‐MS).Extrusion and drum‐dried stabilization significantly increased TPC when compared to non‐stabilized RB (NS‐RB). All stabilization treatments increased antioxidant capacity and radical scavenging activity. uHPLC/online ABTS and LC‐QTOF‐MS identified all treatments to increase the concentration of free phenolic compounds and antioxidant activity compared to NS‐RB. More specifically, drum‐dried RB significantly altered RB phenolic composition when compared to all other treatments.ConclusionsAll stabilization treatments significantly altered TPC and antioxidant activity of RB. Drum‐dried RB treatment was most effective in improving free phenolic composition and antioxidant activity.Significance and noveltyThis study demonstrated that drum‐dried stabilization treatment may be a crucial technique that can be applied to RB to ensure essential phenolic compounds with antioxidant activity remain intact, thereby adding value to the functional and nutritional quality of RB.

Feasibility of ultrasound-assisted optimized process of high purity rice bran protein extraction

ABSTRACT: Rice bran is a by-product of the rice milling process, found worldwide in abundance and highlighted due its protein content. This study optimized the conditions for ultrasonic-assisted extraction of protein from defatted rice bran (DRB) and characterized the rice bran protein concentrate (RBPC). A sequential strategy of experimental design was employed; the effect of pH, temperature, ultrasound exposure time, and amplitude were evaluated regarding the percentage of protein extraction by a Full factorial design (FFD) with a fixed frequencies (FFD-A: 37 kHz; FFD-B: 80 kHz). Subsequently, the percentage of protein extracted was optimized employing a Central composite rotatable design (variables: pH and ultrasound exposure time) and RBPC obtained was characterized regarding chemical and functional properties. The pH and ultrasound exposure time had positive effect (P ≤ 0.05) on percentage of protein extraction; moreover, 37 kHz frequency was more effective in protein extraction. The optimized condition (frequency: 37 kHz; temperature: 30 °C; pH: 10; ultrasound exposure time: 30 min; and amplitude: 100%) allowed 15.07% of protein recovery and the RBPC presented 84.76 g 100 g-1 of protein. Magnesium and copper were the main mineral in RBPC (34.4 and 25.5 µg g-1, respectively), while leucine was the limiting amino acid (0.42) and threonine presented the highest chemical score (1.0). The RBPC solubility was minimal at pH 4 and higher at pHs 6-10; the water and oil absorption capacity were higher than bovine serum albumin (BSA) and the emulsifying capacity was comparable to BSA, with a suitable stability. It was possible to obtain a higher purity RBPC than described in the literature, due to the optimization in the extraction process steps, with functional properties suitable for application in food products, especially emulsified ones.

Antihyperglycemic effect of rice husk derived xylooligosaccharides in high-fat diet and low-dose streptozotocin-induced type 2 diabetic rat model.

Rice husk (RH) is an agricultural waste obtained from rice milling process. Our previous study demonstrated the optimized process of extracting xylooligosaccharides (XOS), a prebiotic that can support the growth and activity of beneficial gut microbiota, from RH. Accumulated evidences indicate that the composition of gut microbiota is involved in the progression of insulin resistance and diabetes. This study aims to evaluate the antihyperglycemic effect and putative mechanisms of RH‐XOS using a diabetic rat model induced by high‐fat diet and streptozotocin injection. Diabetic rats were randomly assigned to receive vehicle (DMC), XOS (DM‐XOS), metformin (DMM), and a combination of XOS and metformin (DMM‐XOS). An additional group of rats were fed with normal diet plus vehicle (NDC) and normal diet plus XOS (ND‐XOS). Supplementation with RH‐XOS for 12 weeks successfully decreased the fasting plasma glucose, insulin, leptin, and LPS levels in DM‐XOS compared with DMC. Likewise, the insulin‐stimulated glucose uptake assessed by in vitro study was significantly enhanced in DM‐XOS, DMM, and DMM‐XOS. The diminished protein expressions of GLUT4 and pAktSer473 as well as pAMPKThr172 were significantly modulated in DM‐XOS, DMM, and DMM‐XOS groups. Interestingly, RH‐XOS supplementation reversed the changed gut permeability, elevated the number of beneficial bacteria, both Lactobacillus and Bifidobacterium spp., and increased SCFAs production. Taken together, the results confirm the efficacy of RH‐XOS in achieving good glycemic control in diabetes by maintenance of gut microbiota and attenuation of endotoxemia. The findings reveal the benefits of RH‐XOS and open an opportunity to improve its value by its development as a nutraceutical for diabetes.

A PROPOSAL ON EFFICIENCY MEASURING OF RICE MILLING PROCESS BY USING AHP / DEA METHOD

Indonesia is a country which becomes the third largest producer of rice in the world. However, Indonesia still carries out rice importing and the rice is classified high-priced. One of the factors causing those problems is the lack of efficiency of rice milling process. Pandeglang Regency is a region which has the largest rice field in Banten. As the largest agricultural territory and a qualified rice producer, it must be possible to have rice-milling means. The rice-milling process does not always produce a constant output amounts, it can be increased or decreased, despite the use of a constant input amounts. Thus, efficiency measuring of rice-milling process is needed to find out the output increase or input decrease used in rice-milling process in order to reach an efficient point. Method applied in measuring the efficiency is AHP/DEA method. Based on acquired research results, the efficiency level at the research location was 90.01% in which from 11 rice-milling processes there was one inefficient rice-milling process which was the C rice-milling process. Keyword: AHP/DEA; efficiency; inefficiency; rice milling process.

Effect of heating using autoclave and microwave on the quality of rice bran as food material

Rice bran is an epidermis of rice produced from 10 - 12% of the rice milling process. Rice bran is susceptible to fat damage due to enzymatic and oxidative processes that cause rancidity, therefore a further process such as heating is needed for stabilization. This study is using the factorial Randomized Block Design (RBD) method, the variables are the type of heating method (autoclave and microwave) and heating duration. Autoclaving (30 min at 75°C) yielded best content value. The heated rice bran has 2.89% water content, 5.79% ash content, 13.87% protein, 7.24% crude fat, 2.68% dietary fibre, 2.04% free fatty acids, and 0.85% peroxides. The contents of free fatty acids, peroxide value, and proximate value from heated rice bran are better than untreated rice bran (control).

Analysis of biomass briquettes based on carbonized rice husk and jatropha seed waste by using newspaper waste pulp as an adhesive material

Biomass waste that has not been utilized properly is rice husk and jatropha seed waste, and there is a future need for efficient utilization of these wastes. Rice husk is the outermost part of the rice seed, the rice milling process produced 20% - 30% of the waste as rice husks. Jatropha shell waste is a de-oiled part of jatropha seed after the oil extraction process for biodiesel production, and produced 70% of waste. As biomass, both materials are potential sources of carbon that can be utilized as an alternative energy sources such as bio-briquettes. The method used in this research is experimental method including drying of the biomass material sample, carbonization process, refine and filtration using 40 mesh sieve (420 μm). The composition of the selected charcoal mixture is 80:20 and 50:50, and the addition of the newspaper waste pulp as an adhesive material with variations of 8% and 12% by weight. Characterization is done by using the mass density test, proximate test and calorific value test. After going through pressure printing and drying process, the briquettes with 8% addition of newspaper waste pulp adhesives has the highest heat energy content, equal to 5,650 cal/g.

Perancangan mesin penghancur sekam padi dengan poros penggerak horisontal

Husk is a waste from the grinding process with the characteristics of a hard, scaly and dry layer. In the rice milling process, according to the Agricultural Research and Development Agency, the Department of Agriculture obtained 20-30% of rice husk, 8-12% of bran and 50 - 63.5% of milled rice. It can be seen that the amount of waste produced is predominantly dominated by rice husk and if not handled it will be a problem for the environment. One effort to reduce the form of waste was carried out research design of rice husk grinding machine become powder. The implementation method starts with designing, manufacturing and testing. The design of the grinding machine is planned to use a fuel motor drive, the transmission uses a V belt and the type of grinder is a combination of discmill and hammermill.The results of research and design obtained rice husk grinding machine with specifications dimensions of 1100 mm high, 400 mm long and 500 mm wide, Hyundai gasoline engine drive HDE 390 with power 7.6 kW, elbow profile frame 50 mm x 50 mm, belt transmission and pulley with a ratio of 1: 1, a combination milling mechanism namely hammer mills which have 3 single hammer attrition mills and a front through grinder with the help of screw conveyor components. The test results of the grinding machine capacity obtained a production capacity of 10 kg / hour, and fuel consumption which is 2.162 liters / hour.

Purification and characterization of α-glucosidase enzyme from rice groats

Groat rice is the side product of rice milling process and potentially producing α-glucosidase. The enzyme has an important role in starch degradation process by breaking α-glycosidic bods to form glucose. This research aimed to understand the optimum activity of the purified α-glucosidase. The research stages are isolation, purification, characterization of substrate concentration, pH level, incubation time, temperature, and effect of metal ion, and dinitrosalicylic acid (DNS) method to determine the activity of α-glucosidase. The result showed the specific activity of α-glucosidase crude extract at 0.003 IU/mg. Fractionation of the highest specific activity on fraction 4 revealed at 0.042 IU/mg and constantly increasing on the dialysis stage at 1.121 IU/mg. α-glucosidase reached optimum activity at substrate concentration 2%, pH of 7, incubation time of 40 minutes, at 37°C, with metal ion Mn2+, Co2+, Na+, Mg2+, Ca2+ and K+ as activators and Zn2+ as inhibitor. α-glucosidase could be used to find analog compounds as the cure of type 2 diabetes mellitus.

Effect of filler and plastisizer on the mechanical properties of bioplastic cellulose from rice husk

Rice husk is a product of the rice milling process. The high cellulose contents in rice husk that supports the use of it as raw material for bioplastic. This study aims to determine the effect of supporting polymer such as chitosan to the mechanical properties of bioplastic. The stages of this research were cellulose extraction from rice husk by maceration method, optimization of NaOCl concentration as a bleaching agent and printing of bioplastics with various treatments, namely cellulose-sorbitol (CS), cellulose-chitosan (CC) and cellulose-sorbitol-chitosan (CSC). Characterization was conducted by Fourier Transform Infrared (FTIR) and Universal Testing Machine (UTM). The study showed that the optimum NaOCl concentration was 2.0% with a cellulose content of 59.2% in the form of white powder. The best bioplastic was bioplastic cellulose-sorbitol-chitosan (CSC) with the tensile strength of 0.060 Kgf/cm2 and the elongation of 4.75%. The peaks appeared in the FTIR spectrum were O-H, N-H and C-O at 3450.64, 1638.41, and 1087.76 cm−1, respectively. The interaction between cellulose from rice husk, filler addition, and plasticizer effected the quality of bioplastic.

Rice Bran Reduces Weight Gain and Modulates Lipid Metabolism in Rats with High-Energy-Diet-Induced Obesity

Obesity has become an epidemic worldwide. It is a complex metabolic disorder associated with many serious complications and high morbidity. Rice bran is a nutrient-dense by product of the rice milling process. Asia has the world’s highest rice production (90% of the world’s rice production); therefore, rice bran is inexpensive in Asian countries. Moreover, the high nutritional value of the rice bran suggests its potential as a food supplement promoting health improvements, such as enhancing brain function, lowering blood pressure, and regulating pancreatic secretion. The present study evaluated the anti-obesity effect of rice bran in rats with high-energy diet (HED)-induced obesity. Male Sprague–Dawley rats were randomly divided into one of five diet groups (n = 10 per group) and fed the following for eight weeks: Normal diet with vehicle treatment, HED with vehicle, rice bran-0.5X (RB-0.5X) (2% wt/wt rice bran), RB-1.0X (4% wt/wt rice bran), and RB-2.0X (8% wt/wt rice bran). Rice bran (RB-1.0X and RB-2.0X groups) markedly reduced obesity, including body weight and adipocyte size. In addition, treating rats with HED-induced obesity using rice bran significantly reduced the serum uric acid and glucose as well as the liver triglyceride (TG) and total cholesterol (TC). Furthermore, administration of an HED to obese rats significantly affected hepatic lipid homeostasis by increasing phosphotidylcholine (PC; 18:2/22:6), diacylglycerol (DG; 18:2/16:0), DG (18:2/18:1), DG (18:1/16:0), cholesteryl ester (CE; 20:5), CE (28:2), TG (18:0/16:0/18:3), and glycerol-1-2-hexadecanoate 3-octadecanoate. However, the rice bran treatment demonstrated an anti-adiposity effect by partially reducing the HED-induced DG (18:2/18:1) and TG (18:0/16:0/18:3) increases in obese rats. In conclusion, rice bran could act as an anti-obesity supplement in rats, as demonstrated by partially reducing the HED-induced DG and TG increases in obese rats, and thus limit the metabolic diseases associated with obesity and the accumulation of body fat and hepatic lipids in rats.

Experimental investigation and energy analysis of a solar-assisted fluidized-bed dryer including solar water heater and solar-powered infrared lamp for paddy grains drying

During drying process of paddy grains, as one of the major operations of rice milling process, a considerable amount of fossil fuel is consumed. The air pollutants emitted by combustion of fossil fuels are great threat to human health which strongly contribute to environmental problems. In the present study, to reduce the share of fossil fuels in drying process of paddy grains, a new type solar-assisted fluidized-bed dryer was used with the ability of thermal energy recovery. The drying system mainly consisted of a solar water heater, a solar-powered infrared lamp, a gas water heater, and a desiccant wheel. Two general conditions were considered for conducting the experiments: Natural gas drying (NGD), and Solar-assisted drying (SAD). The results of evaluations showed that the highest total energy consumption of the dryer was equal to 1.163 kWh which was obtained in NGD test mode, while the lowest amount of total energy consumption was obtained in SAD mode which was 0.314 kWh. The specific energy consumption of the drying system in SAD and NGD modes was in the range of 8.30–22.12 and 16.73–32.62 kWh/kg water evaporated, respectively. The highest value of solar fraction index was equal to 0.538 which was obtained at drying air temperature of 45 °C, drying air velocity of 8 m/s, while the lowest solar fraction value (0.179) was attributed to drying air temperature of 35 °C and air velocity of 7 m/s. Although applying the infrared lamp caused the solar energy fraction to increase to 0.741, however, the use of infrared lamp in the fluidizing chamber did not have a significant effect on the dehydration rate of the product. At two levels of the applied drying temperatures (35 °C and 45 °C), the required thermal energy during the drying process was completely supplied only by solar energy and without the need for fossil fuel.

A modified mid-level data fusion approach on electronic nose and FT-NIR data for evaluating the effect of different storage conditions on rice germ shelf life

Evaluating the possibility of extending shelf life of rice germ (a by-product of rice milling process) by reducing water activity in combination with storage atmosphere packaging, without any heat treatment, is the aim of the present study. Samples at different water activities (0.55, 0.45 and 0.36) were packed in air, argon or under vacuum, and stored at 27 °C for 150 days. To the aim, a non-targeted approach was applied by means of an FT-NIR spectrometer in reflectance with a rotating sample holder and a portable electronic nose, equipped with 10 non-specific sensors. For understanding the impact of the factors under study on the rice germ shelf life, a modified mid-level data fusion approach was applied to enhance the information most correlated with time. Moreover, Principal Component Analysis was applied on fused data to follow samples evolution during storage and identify different clusters according to the storage conditions. The rice germ case study allowed to better understand the information captured by the non-specific sensors: a 2D correlation map was developed combining the e-nose data with the NIR spectral information, highlighting relationships among NIR absorption bands and classes of chemical compounds inducing e-nose responses. A data fusion approach highlighted the importance of water activity on rice germ storage, while no interesting differences were ascribable to storage atmosphere packaging systems. In terms of correlation, the sensors could be divided in two groups, negatively inter-correlated: sensors ascribable to aromatic compounds (WC) and correlated with the NIR band around 4800–4900 cm−1 (N–H bending of primary amides, typical for peptides coming from protein hydrolysis); broad-range response sensors (WS), linked with the NIR band at 5128 cm−1 (second overtone of CO stretching of esters).