Revealing the mechanism of post-harvest processing on rose quality based on dynamic changes in water content, enzyme activity, volatile and non-volatile metabolites.

Existing studies on post-harvest processing of edible roses have mainly focused on processing techniques and physicochemical properties of the final dried products, with limited studies on how changes in metabolites during processing affect the quality of these products. This study investigated changes in water content and status, enzyme activity, phenolic compounds, and volatile and non-volatile compounds during processing and revealed the mechanisms by which post-harvest processing (drying without blanching (WBD) and drying with blanching (BD)) affects the quality of dried roses by establishing their correlations. Results showed that the blanching reduced the relative content of free water and water activity, thus reducing the subsequent drying time and enzyme activity. The BD method caused higher levels of phenolic compounds than the WBD method in terms of gallic acid, ellagic acid, epicatechin, and quercetin. The OPLS-DA analysis identified 6 differential volatiles out of 72 detected volatiles, contributing to the unique aroma of dried roses by activating olfactory receptors through hydrogen bonding and hydrophobic interactions. 58 differential metabolites were screened from 964 non-volatile metabolites. KEGG pathway analysis revealed that the changes in volatile and non-volatile metabolites induced by different processing methods were due to the effect of blanching on glutathione and fatty acid metabolism. These findings provide a comprehensive understanding of how post-harvest processing affects the quality of dried roses.

Effect of various different pretreatment methods on infrared combined hot air impingement drying behavior and physicochemical properties of strawberry slices.

In current work, the effect of freezing (F), ultrasound (U), and freeze- ultrasound (FU) pretreatment on infrared combined with hot air impingement drying kinetics, cell ultrastructure, enzyme activity, and physicochemical properties of strawberry slices were explored. Results showed that FU pretreatment enhanced cell membrane permeability via forming micropores, altered water status by transforming bound water into free water and thus promoted moisture diffusivity and decreased drying time by 50% compared to the control group. FU pretreatment also extensively decreased pectin methylesterase enzyme activity and maintained quality. The contents of total phenols, anthocyanins, vitamin C, antioxidant activity, and a* value of dried strawberries pretreated by FU were extensively increased compared to the control group. U and FU pretreatments were beneficial for retaining aromatic components and organic sulfides according to e-nose analyses. The findings indicate that FU is a promising pretreatment technique as it enhances drying process and quality of strawberry slices.

Comparative evaluation of drying methods for struvite produced from electrocoagulated source-separated urine: Implications for quality, energy and cost-effectiveness.

Struvite precipitation from source-separated urine is crucial for waste utilization and sustainability. However, after precipitation, the high moisture content of struvite necessitates an additional drying process that can be costly and inefficient. In the present study, the performance of different drying methods-open sun drying, air drying, conventional drying (20-100 °C), and microwave drying (180-720 W) on the quality of struvite obtained from source-separated urine through electrocoagulation using Mg-Mg electrodes were evaluated. It was found that higher temperatures and power in the convective oven and microwave resulted in higher diffusivity (10-9-10-7 m2s-1), leading to reduced drying times. Different models were employed to comprehend the drying mechanism, and the one with the highest correlation coefficient (R2 = 0.99) and the lowest statistical values was selected. The key findings indicated that higher power and temperature levels were more cost-effective. However, characterization of the dried struvite using X-ray diffraction and Fourier-transformed infrared spectroscopy, disintegration of struvite crystals at temperatures above 60 °C in the conventional oven and 180 W in the microwave oven was observed. Based on the results, we conclude that sun drying is a cost-effective and environmentally friendly alternative for drying struvite without compromising its quality.

Peeling mechanism of tomato induced by HHAIB: Microscopic, ultrastructure, chemical, physical and mechanical properties perspectives.

In order to better manage the peeling degree and avoid unnecessary losses, the current work aimed to explore the peeling mechanism of a novel peeling technology, high-humidity hot air impingement blanching (HHAIB). The relationships between HHAIB peeling performance and the changes in skin temperature, skin structure, water state, pectin fractions content, and skin mechanical properties of tomatoes were analyzed. Results showed, after HHAIB treatment, the epicuticular wax was disrupted, the skin exhibited more and longer random cracks, the degradation of inner skin tissue was observed by transmission electron microscopy, the free water percentage increased resulting in water loss in the whole tomato, the water-soluble pectin contents decreased in tomato fleshes, while the contents of chelate-soluble pectin and sodium-carbonate-soluble pectin increased. HHAIB heating reduced the elongation at break, and increased Young's Modulus of tomato peel. This study revealed the HHAIB peeling mechanism and provided new insights for developing HHAIB peeling technology.

Spectral selective infrared heating of food components based on optical characteristics and penetration depth: a critical review.

Infrared (IR) radiation has been used in food processing applications for its unique high heating efficiency. There is a great need to address the radiation absorption and heating effect during the application of IR in the processing of foods. The radiation wavelength determines the nature of the processing, and it is mainly affected by the type of emitter, operating temperature, and the power supplied. The penetration depth of the IR on food material plays a critical role in the heating level along with the optical characteristics of the IR and food product. The IR radiations cause a significant change in the food components like starch, protein, fats and enzymes. The facility to generate wavelength-specific radiation output can hold the potential of momentously increasing the efficiency of IR heating operations. IR heating is gaining importance in 3D and 4D printing systems, and the application of artificial intelligence in IR processing is being explored. This state-of-art review gives a detailed view of the different emitters of IR and mainly emphasizes the behavior and changes of major food components during IR treatment. The penetration depth of IR, optical characteristics and selective spectral heating based on the target product are discussed.

Development of effluent-free dry-peeling method for shallots (Allium cepa L. aggregatum): Spectral characterization of mid and long infrared peak wavelengths for maximizing the peeling performance.

Different wavelength emitting infrared (IR) lamps (transparent quartz tungsten (TQT), ruby-coated quartz tungsten (RCQT), and ceramic) were used for dry peeling and evaluating the spectral characteristics of emitted radiations. The maximum temperatures for ceramic, RCQT, and TQT were 560, 662, and 861°C, respectively. The peak wavelength determined by Wien's law was between 3.37 and 21.47 µm. Comparatively, longer wavelength was emitted by ceramic lamp. The spectral emissive power determined by Stefan Boltzmann's law was 1.14-37.49 kW m-2 using the IR emitters at different power levels. The radiant efficiency was higher for the ceramic lamp. The peak wavelength and emissive power had a major influence on the peeling performance and quality during IR peeling. The optimized parameters for IR dry peeling of shallots are 60 mm distance between lamp and product, 59.74% IR power level, 15 min of heating time using the ceramic (peak wavelength 8.16 µm) lamp. Practical Application: Infrared dry peeling of shallots is a sustainable alternative to traditional peeling methods that leaves adverse environmental footprints. Spectral characteristics of the infrared lamp can be used to determine the suitable emitter for the dry-peeling operation. It is necessary to check the wavelength emitted by the source for designing the IR system based on the food product and application. This study will be helpful in food processing industries to use an effective infrared lamp that can efficiently peel the agricultural product and sustainably maintain quality.

Characterization and identification of inulin from Pachyrhizus erosus and evaluation of its antioxidant and in-vitro prebiotic efficacy.

Inulin is the polysaccharide obtained from different plant sources i.e. Wheat, Chicory, Jerusalem artichoke and Dahlia. In this study, Jicama (Pachyrhizus erosus) is used to isolate inulin using the microwave heating. The 1H NMR study reveals the presence of fructose and glucose unit which is the backbone of inulin. Further FT-IR and Raman confirmed the functional groups present in inulin. The UV-Vis spectroscopy analysis depicts the purity of the isolated inulin. The shape and size of the extracted inulin was determined from scanning electron microscopy and dynamic light scattering appeared as flat-flakes and 135 nm respectively. X-ray diffractogram showed semi-crystalline nature suggesting the stability of the extracted inulin. The isolated inulin has phenolic and flavonoid content of 8.1804 ± 6.26 mg gallic acid equivalent/g and 14.387 ± 4.192 mg rutin equivalent/g of dried polysaccharide respectively. The inhibition percentage of DPPH and FRAP of isolated inulin were found to be 75.74 ± 4.5% and 0.11 ± 0.007 respectively. The isolated inulin promotes the growth of probiotics like Enterococcus faecium (MZ540315) and Lactiplantibacillus plantarum (MZ540317). All the analysis suggest the isolated inulin has good prebiotic potential as the commercially available one. The current study proposes that isolated inulin can be used as a prebiotic in the future. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05619-6.

Evaluation of effect of vacuum frying on textural properties of food products.

Vacuum frying (VF) is known as the most popular food processing method for the production of ready-to-eat snacks. It includes simultaneous mass and heat transfer in very low temperature and frying period to provide higher qualitative products. The quantity of oil used for frying is less in the vacuum frying method as compared to other frying methods. Numbers of physical, chemical, and structural changes occur during the frying process by evaporation of moisture, obstruction of oil movement, gelatinization of starch, denaturation of protein structure, and solubilization of pectin cells. These changes lead to textural modification of fried products and VF successfully enhances the textural properties at optimum process parameters which are according to the consumers' acceptance. In this context, this review is an update of the VF, showing the effect of different process parameters on the improvement of the texture of the fried snacks. Additionally, the mechanism behind the development of texture due to VF has been described in detail along with proper figures. Also, a comparative study of VF and atmospheric conventional frying on the increment of textural characteristics in various food materials starting from fruits and vegetables to fish and meat products have been highlighted. Moreover, to enhance the food texture during VF, several pre/post frying treatments are carried out which have been taken into discussion. Further, some novel techniques adopted along with VF, which influence highly on texture development of food materials, have been mentioned.

Inulin-A polysaccharide: Review on its functional and prebiotic efficacy.

The intake of dietary fibers in the regular diet results in boosting the gut microbiome and health of the host in several ways. The misapprehension about such dietary fibers of being only an indigestible product has changed into indispensable ingredient that has to be included in every healthy diet. Inulin is considered to be an important naturally occurring fructan classified under such dietary fibers. The present review intends to provide a thorough knowledge on inulin in maintaining the gut microbiome of the human, supported by several studies conducted on the Drosophila melanogaster, mice, rat models as well as effect on human being. The extraction process of inulin has also been described in this review that would provide a brief knowledge about its stability and the conditions that have been optimized by the researchers in order to obtain a stable product. PRACTICAL APPLICATIONS: In order to meet the consumers demand, the food industries are trying to come up with new products that could eventually replace or lower the utilization of medically avail drugs and satisfy consumers by providing them with health benefits. The availability of functional food is the new trend that can improve health of the consumers with minimal use of the drugs. Therefore, inulin as a prebiotic can be utilized to produce several functional food products that could promote health benefits to the consumers. Apart from this, the review also justifies the efficacy of inulin as a fat replacer, stabilizer, and humectant in cosmetic industries. Research also suggests that inulin has also been used as nanoparticles in pharmaceutical industries. The overall review also depicts the different extraction process of inulin from different sources.

Treating the Onset of Diabetes Using Probiotics Along with Prebiotic from Pachyrhizus erosus in High-Fat Diet Fed Drosophila melanogaster.

The increasing mortality due to hypertension and hypercholesterolemia is directly linked with type-2 diabetes. This shows the lethality of the disease. Reports suggest that the prebiotics along with probiotics help in lowering the effects of type-2 diabetes. Prebiotic like inulin is best known for its anti-diabetic effect. The current study utilizes jicama extract as prebiotic source of inulin along with the bacterial strains with probiotic properties (Lactiplantibacillus plantarum and Enterococcus faecium) for treating type-2 diabetes in high-fat diet-induced Drosophila melanogaster model. The high-fat diet-induced Drosophila showed deposition of lipid droplets and formation of micronuclei in the gut. The larva and adult treated with probiotics and synbiotic (probiotic + prebiotic- inulin) comparatively reduced the lipid deposition and micronuclei number in the gut. The increased amount of triglyceride in the whole body of the fatty larva and adult indicated the onset of diabetes. The overexpression of insulin-like genes (Dilp 2) and (Dilp 5) confirmed the insulin resistance, whereas the expression was reduced in the larva and adult supplemented with probiotics and synbiotic. The reactive oxygen species level was reduced with the supplementation of probiotics. The weight, larva size, crawling speed and climbing were also altered in high-fat diet-induced Drosophila melanogaster. The study confirmed the effects of probiotics and synbiotic in successfully lowering diabetes in Drosophila. The study also proved the anti-diabetic potential of the probiotics. Further, it was also confirmed that the probiotics work better in the presence of prebiotic.

Thermal Decontamination Technologies for Microorganisms and Mycotoxins in Low-Moisture Foods.

The contamination risks of microorganisms and mycotoxins in low-moisture foods have heightened public concern. Developing novel decontamination technologies to improve the safety of low-moisture foods is of great interest in both economics and public health. This review summarizes the working principles and applications of novel thermal decontamination technologies such as superheated steam, infrared, microwave, and radio-frequency heating as well as extrusion cooking. These methods of decontamination can effectively reduce the microbial load on products andmoderately destruct the mycotoxins. Meanwhile, several integrated technologies have been developed that take advantage of synergistic effects to achieve the maximum destruction of contaminants and minimize the deterioration of products.

Effects of vacuum-steam pulsed blanching on drying kinetics, colour, phytochemical contents, antioxidant capacity of carrot and the mechanism of carrot quality changes revealed by texture, microstructure and ultrastructure.

An emerging blanching technology, namely vacuum-steam pulsed blanching (VSPB) was employed to blanch the carrots and its effects on blanching efficiency, microstructure and ultrastructure, drying kinetics, colour, texture, phytochemicals (phenolics and ß-carotene) and antioxidant capacity of carrot slices were explored and compared with the traditional hot water blanching. Results showed that both blanching treatments enhanced the drying velocity and shortened the drying time by 25.9% compared with untreated samples. VSPB yielded higher blanching efficiency, better colour (more red and yellow), greater antioxidant capacity and higher preservation of phytochemicals compared with hot water blanched samples. Especially, compared to hot water blanched carrots, the p-hydroxybenzoic acid, ferulic acid, and caffeic acid content of VSPB samples increased of 106.6%, 42.0%, and 19.0%, respectively. Interestingly, the chlorogenic acid content in the blanched carrot increased more than 220 times compared to fresh samples. Ultrastructure and microstructure observation clarify the mechanism of quality enhancement of VSPB.

Effluent free infrared radiation assisted dry-peeling of ginger rhizome: A feasibility and quality attributes.

Infrared radiation (IR)-assisted peeling is one of the effulent free, environtment friendly emerging technique for tender fruit and vegetables. In this study standerdization and optimization of the infrared assisted dry-peeling method was carried out for ginger rhizome. During the investigation, the effects of selected independent parameters like infrared temperature (300-400 °C), heater to product surface spacing (10-30 mm), and treatment time (120-300 s) were studied on the peeling feasibility and quality as dependent variables. The experimental conditions were designed through CCRD statistical method. Multiple response optimization was done through RSM. The optimum conditions of selected independent variables were 300 °C IR temperature, 21 mm heater to product spacing, and 120 seconds treatment time resulted in the 90.40% of peeling efficiency, 35 °C of rhizome surface temperature, 8.67% of color change, 0.56% volatile oil loss, and 11.53 kg of firmness. The comparison of optimized infrared assisted peeling was carried out with conventional abrasion and lye peeling methods based on their quality attributes. IR assisted dry-peeling results in minimum quality losses, higher peeling efficiency and feasible over conventional peeling methods of ginger rhizome. There was zero effluent generated during infrared assisted peeling of ginger rhizome. PRACTICAL APPLICATION: Peeling is one of the foremost mandatory unit operation for processing of all fruits, vegetables, and rhizomes like ginger. Presently, lye peeling is most widely used peeling method in industries followed by mechanical peeling. Both of these methods have serious issues like huge effluent generation (BOD) and water consumption which leads to the concern about environmental issues. Infrared dry peeling is the most prominent alternative for industries having the potential to deals with environmental issues. IR peeling method can be easily designed and scaled-up as per the specific requirment of industries. Therefore, understanding its feasibility for peeling of a most difficult commodity like ginger and understanding its insight into the quality of peeled product is need of the hour.