Kiwifruit Peel Research Articles

Sustainable kiwi fruit derived carbon dots architected WO3 (KF-CDs@WO3) thin films based flexible electrochromic devices with improved stability for next generation smart windows applications

The design and development of new advanced materials or technologies are essential for the construction of high performance smart windows for the next generation of energy efficient buildings. Tungsten trioxide (WO3) based flexible electro-chromic devices f-ECDs have received extensive attention for the development of next generation f-ECDs. Here, we demonstrated the design and fabrication of kiwi fruit peel derived carbon dots (KF-CDs) decorated WO3 films under benign approaches. Furthermore f-ECDs were developed and their performance have been examined in terms of transmittance and coloration efficiency. The amount of KF-CDs in to the WO3 was varied and optimized f-ECDs exhibited the excellent optical contrast (ΔT) of 83.74 %, coloration efficiency of 86.2 cm2/C. The optimized f-ECDs exhibited excellent cyclic stability of 25000th cycles and retained more than 80 % optical contrast compared to the initial performance. This improved stability may be attributed to the presence of strong hydrogen bonding between the functional groups of KF-CDs and WO3.

Catalytic Degradation Efficacy of Silver Nanoparticles Fabricated Using Actinidia deliciosa Peel Extract

The preparation of metallic nanoparticles using green synthetic approaches and its application toward the efficient degradation of environmentally hazardous dyes constitutes an attractive alternative to currently employed methods. In the current report, the green synthesis of silver nanoparticles (AgNPs) was successfully achieved using Actinidia deliciosa (kiwifruit) peel aqueous extract as a bioreducing agent under optimized synthesis conditions. The experimental parameters were optimized in terms of reactant ratio, reaction temperature, and reaction time. The biogenic nanoparticles exhibited SPR absorption band at λmax 480 nm. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed quasispherical monodisperse nanoparticles which were 36 nm in diameter. The hydrodynamic diameter of the nanoparticles was 106 nm as determined by dynamic light scattering, and the highly negative ζ-potential (−34 mV) supported its superior colloidal stability. Energy dispersive X-ray confirmed that silver is a major constituent of the nanoparticles. X-ray diffraction (XRD) diffractograms confirmed the crystallinity of the nanoparticles and its face-centered cubic (fcc) lattice structure. The functional groups in the plant’s phytochemicals facilitating the reduction of Ag+ ions and stabilization of the formed AgNPs were identified by fourier transform infrared (FTIR) spectroscopy. In specific, the bands in the FTIR spectra at 3,412, 1,618, 1,419, and 1,237 cm−1 suggested the presence of phenolic compounds. Phytochemical analysis by colorimetric assays revealed that the kiwifruit peel extract was rich in phenolic compounds. When evaluated in the catalytic degradation of organic dyes, the biosynthesized AgNPs induced instant and complete discoloration of the methylene blue dye when 1.6 mg of nanoparticles was used. At a lower dose of AgNPs (0.4 mg), 80% degradation of the dye occurred after 3 hr of treatment. The degradation reaction followed second-order kinetics with a rate constant of 0.01083 mM−1s−1. The current study highlights the immense potential of the prepared nanoparticles as efficient catalysts for the degradation of hazardous organic dyes such as methylene blue and presents an intriguing argument for investigating the catalytic efficiency of the biogenic AgNPs for the degradation of other structurally different dye pollutants.

Kiwifruit Peel Extract Improves the Alterations in Lipid Metabolism in High-fat Diet-fed Model Rats.

Previous studies have demonstrated that the kiwifruit peel, which is usually discarded by consumers and factories, has the highest polyphenol content among all parts of the kiwifruit. To maximize the utilization of these waste resources, the aim of this study was to examine the regulatory effects of polyphenols extracted from kiwifruit peel (KPE) on lipid metabolism and investigate their underlying mechanisms. Thirty-two male Sprague‒Dawley rats were divided into four groups: those fed a normal diet, those fed a high-fat (HF) diet, and those fed a HF diet with a low dose of KPE solution (50 mg/kg) or a high dose of KPE (100 mg/kg) by gavage. The findings of the study revealed that KPE effectively reduced body weight gain and the increases in triglycerides and total cholesterol in serum induced by the HF diet (HFD). Additionally, KPE supplementation led to a significant decrease in hepatic fat accumulation, potentially by increasing hepatic oxidation abilities. Hepatic lipidomics demonstrated that KPE influenced various metabolic pathways, including linoleic acid metabolism, steroid biosynthesis, and the biosynthesis of unsaturated fatty acids in HFD-induced rats, which were associated with the downregulation of FATP2, ACC, FAS, GPAT, DGTA1, DGTA2, and PPARγ expression as well as the upregulation of AMPK, PGC-1α, CPT-1, and PPARα expression. These findings suggest that KPE has considerable regulatory effects in rats with dyslipidaemia, which may provide supporting information for the reuse of kiwifruit peel.

Kiwi Fruit Peel Biowaste Mediated Green Synthesis of Silver Nanoparticles for Enhanced Dye Degradation and Antibacterial Activity

Kiwi Fruit Peel Biowaste Mediated Green Synthesis of Silver Nanoparticles for Enhanced Dye Degradation and Antibacterial Activity

Facile Fabrication of N-doped Carbon Derived from Kiwi Fruit Peel for Advanced Supercapacitor

As a potential material, biomass material has become a hot spot for energy storage equipment because of its enhanced properties and environmental-friendly features. Waste kiwi fruit peel is a kind of biomass material with a natural macroporous structure. After carbonization, acid pickling and activation, the kiwi fruit peel carbon (KFPC) with a 3D porous structure composed of macropores, mesopores and micropores on its surface and inner channels, respectively. The morphology and structure of the KFPC are studied by scanning electron microscopy (SEM). The electrochemicial properties were analyzed in a three-electrode system. The cyclic voltammetry (CV) measurement at the scan rate of 5-100 mV s-1 in 2 M KOH aqueous electrolyte. The Galvanostatic charge/discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) are used to calculate the specific capacitance and resistance, respectively. The KFPC exhibits a 2290 m2 g-1 specific surface area. The capacitor has a specific capacitance of 249.8F g− 1 at 1 A g− 1 and a capacity retention rate of 89.22 % after 5000 cycles at 5 A g− 1, indicating that the KFPC is relatively stable. After assembling the materials into a symmetric supercapacitor, it delivered a high energy density of 9.75 Wh kg-1, which reveals the promising application of KFPC in high-performance supercapacitors.

Effects of Green Kiwifruit Peel Extract on Sleep-Wake Profiles in Mice: A Polysomnographic Study Based on Electroencephalogram and Electromyogram Recordings.

In the previous study, it was reported that green kiwifruit peel ethanol extract (GKPEE) increases sleep duration and decreases sleep latency in pentobarbital-treated mice. The pentobarbital-induced sleep test can be used to verify sleep quantity, which includes factors such as sleep duration and latency, but not sleep quality. In the present study, the sleep-promoting effects of GKPEE were investigated by the analysis of electroencephalogram (EEG) and electromyogram in mice and were compared with the results of diazepam (DZP), a representative sedative-hypnotic agent. The acute administration of GKPEE (250, 500 and 1000 mg/kg) increased the amount of non-rapid eye movement sleep (NREMS) and decreased sleep latency in a dose-dependent manner. The effect of GKPEE at 1000 mg/kg produced persistently significantly different results until the second hour of time-course changes. In particular, GKPEE did not produce any change in delta activity compared to DZP. Furthermore, sub-chronic administration (15 days) of GKPEE (500 mg/kg) continued sleep-promoting effects, whilst the EEG power density of NREMS did not show significant differences, indicating that there were no tolerance phenomena. Our findings suggest that GKPEE may be a promising natural sleep aid for treating sleep disorders. In addition, considering the number of by-products discarded each year by the food industry, the application of GKPEE here contributes to the utilization of processed kiwifruit by-products and can help to solve environmental problems.

Effect of hardness on the mechanical properties of kiwifruit peel and flesh

ABSTRACT The mechanical properties of kiwifruit serve as the foundation for mechanical damage. In this work, the effect of hardness on the mechanical properties of kiwifruit was explored, and a hardness-mechanical property prediction model was developed. The results in this study showed that the tensile strength of the kiwifruit peel increased with decreasing hardness by 0.51, 0.75, 0.83, and 1.02 MPa in the axial direction and 0.48, 0.68, 0.92, and 1.08 MPa in the radial direction, respectively. While the peel’s elastic modulus decreased by 21.15, 14.03, 11.87, and 10.52 MPa in the axial direction and 15.04, 10.68, 8.45, and 7.54 MPa in the radial direction. At the same ripening stage, peel tensile strength did not differ significantly (P > .05), whereas peel modulus of elasticity was greater in the axial direction than in the radial direction. The results of the flesh compression test showed that the compressive strength of the flesh decreased with decreasing hardness to 0.36, 0.25, 0.09, and 0.06 MPa in the axial direction and 0.36, 0.23, 0.11, and 0.06 MPa in the radial direction, respectively. The modulus of elasticity also decreased to 1.05, 0.82, 0.42, and 0.32 MPa in the axial direction and 0.26, 0.45, 0.80, and 1.15 MPa in the radial direction, respectively. The compressive strength and modulus of elasticity of kiwifruit flesh did not differ significantly in the axial and radial directions at the same stage of ripening (P > .05). The model’s accuracy is demonstrated by correlation coefficients of tensile strength (compressive strength) and elastic modulus of kiwifruit peel and pulp in axial and radial directions, which were 0.97, 0.99 (0.99, 0.99), and 0.93, 0.90 (0.96, 0.99), respectively, for anticipating the mechanical characteristics of peel and flesh. It can provide theoretical and data references for post-harvest kiwifruit to reduce the mechanical damage.

Antioxidative Properties and Phenolic Profile of the Core, Pulp and Peel of Commercialized Kiwifruit by LC-ESI-QTOF-MS/MS

The kiwifruit is cultivated globally due to its diversity of phytochemicals, especially phenolic compounds, which have antioxidant, anti-inflammatory and anti-cancer medical effects. However, only the pulp of the kiwifruit is consumed, while the peels and cores—which are also rich in phytochemicals—are usually wasted. Meanwhile, detailed information on the comparison among the three parts is still limited. In this study, the antioxidant potentials in the core, pulp, and peel of the three most commercialized kiwifruit cultivars (Australian-grown Hayward kiwifruit, New Zealand-grown Zesy002 kiwifruit, and New Zealand-grown organic Hayward kiwifruit) were selected. Their antioxidant capacities were tested, and their phenolic profiles were identified and characterized by liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS). The antioxidant results showed that the peel of New Zealand-grown organic Hayward kiwifruit contained the highest total phenolic content (9.65 mg gallic acid equivalent (GAE) mg/g) and total antioxidant capacity (4.43 mg ascorbic acid equivalent (AAE) mg/g), respectively. In addition, the antioxidant capacity of the peel is generally higher than that of the pulp and cores in all species, especially ABTS (2,2-Azino-bis-3ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging ability), ranging from 13.25 mg AAE/g to 18.31 mg AAE/g. The LC-ESI-QTOF-MS/MS tentatively identified the phenolic compounds present in the three kiwifruit species, including 118 unique compounds in kiwifruit peel, 12 unique compounds in the kiwifruit cores, and three unique compounds in kiwifruit pulp. The comprehensive characterization of the phenolics in the kiwifruits’ parts indicates the importance of their waste part as a promising source of phenolics with antioxidant properties. Therefore, this study can guide the industry with meaningful information on kiwifruit waste, and can provide it with the utilization of food and pharmacological aspects.

An Easy and Cheap Kiwi-Based Preparation as Vegetable Milk Coagulant: Preliminary Study at the Laboratory Scale.

In the present study, a kiwifruit aqueous extract was developed and used as a coagulant enzyme in cheesemaking. In detail, polyacrylamide gel electrophoresis (SDS-PAGE) was used to investigate the presence of actinidin, the kiwifruit enzyme involved in κ-casein hydrolysis, in different tissues (pulp, peel, and whole fruit) of ripe and unripe kiwifruits. Data revealed the presence of the enzyme both in the peel and in the pulp of the fruit. Although the aqueous extract obtained from the kiwifruit peel was able to hydrolyze semi-skimmed milk, it did not break down κ-casein. The aqueous extract obtained from the pulp showed a hydrolytic activity toward both κ-casein and semi-skimmed milk. The values for milk-clotting and proteolytic activity of the kiwifruit pulp extract were evaluated at different temperatures and pH parameters in order to obtain a high value of the MCA/PA ratio; we found that a temperature of 40 °C in combination with a pH value of 5.5 allowed us to obtain the best performance. In addition, the data revealed a higher hydrolytic activity of the enzymatic preparation from ripe kiwifruits than that from unripe ones, suggesting the use of the extract from pulp of ripe kiwifruits in the laboratory-scale cheesemaking. The data showed that 3% (v/v) of the ripe kiwifruit pulp extract determined a curd yield of 20.27%, comparable to chymosin yield. In conclusion, the extraction procedure for kiwifruit aqueous extract proposed in the present study was shown to be a fast, cheap, chemical-free, and ecofriendly technology as a plant coagulant for cheese manufacturing.

Effects of Kiwifruit Peel Extract and Its Antioxidant Potential on the Quality Characteristics of Beef Sausage.

In the wake of arresting consumers’ health concerns associated with synthetic antioxidants used in meat products, kiwifruit peel by-product was explored as a natural antioxidant source in the current study. A lyophilized kiwifruit peel extract (KPE) at various concentrations of KPE1 (1.5%), KPE2 (3%), and KPE3 (4.5%) was incorporated into formulated beef sausages to compare the physicochemical, sensory quality, and antioxidant efficacy to the treatments of control (CT 0% KPE) and butylated hydroxytoluene (BHT 0.01%) during 12 d of refrigerated (4 ± 1 °C) storage. The KPE inclusion levels induced significantly higher yellowness (b*) values than CT and BHT, whereas no negative influence of KPE was revealed for lightness (L*) and redness (a*). The pH values of the KPE treatments were reduced, and cooking yield increased significantly (p < 0.05), in line with the increasing amount of KPE percentages (1.5%, 3%, and 4.5%) compared to CT and BHT samples. E-nose results showed an enhancement in aroma in KPE treatments, compared to BHT and CT, during the storage period. KPE3 treatment showed a constant lesser value in 2-Thiobarbituric acid reactive substances (TBARS) as storage days increased, compared to the CT and BHT samples. Overall, the KPE is effective for antioxidative capacity, and has the potential to be used as a natural antioxidant in beef sausage.

Tunable fluorescent carbon dots from biowaste as fluorescence ink and imaging human normal and cancer cells

Growing global biowaste and its environmental issues challenge the need for converting biowastes into a beneficial product. Among the biowaste, here kiwi fruit (Actinidia Deliciosa) peels are considered for the preparation of carbon dots (CDs). Using a green one-pot hydrothermal-carbonization method, kiwi fruit peels were effectively converted into valuable kiwi fruit peel carbon dots (KFP-CDs). The morphology, physio-chemical and optical properties of as-synthesized KFP-CDs were analyzed using various analytical techniques such as X-ray powder diffraction, Raman spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Ultraviolet–visible, and fluorescence spectroscopy. The KFP-CDs revealed a homogeneous spherical shape, monodispersed with an average size of 5 nm. The characterization confirms that KFP-CDs have functional groups such as –CN, –COOH, and –OH which are responsible for the easy dispersion of KFP-CDs in aqueous media. Without any preprocessing, KFP-CDs exhibit strong fluorescence upon exposure to UV light. Further, KFP-CDs displayed excitation-dependent fluorescence emission with a good quantum yield of about 18%. Thus by considering the excellent properties of KFP-CDs, KFP-CDs were used as fluorescent ink for drawing and writing without any capping/passivation agent. The pictures and words were instantaneously viewed when exposed to UV light. In addition, KFP-CDs tested for cell imaging in four human cell lines (normal and cancer cells) bestowed excellent biocompatibility and low cytotoxicity, which is important for the safe and long-term development of cellular imaging. The findings imply that KFP-CDs can be utilized as a cell labeling agent for mesenchymal stem cells, breast cancer, and thyroid cancer cells in vitro imaging. Thus, these observations revealed that investigating sustainable resource-based CDs can open up new avenues for tackling environmental issues.

Gastroprotective Effects of Spirulina platensis, Golden Kiwifruit Flesh, and Golden Kiwifruit Peel Extracts Individually or in Combination against Indomethacin-Induced Gastric Ulcer in Rats.

This study was conducted to investigate the therapeutic effect of hydro-alcoholic extract of Spirulina platensis (SP), golden kiwifruit (Actinidia chinensis) flesh (KF), and golden kiwifruit peel (KP) individually or in combination (SFP) on indomethacin-induced gastric ulcer in rats. Negative control rats (GI) were orally administered distilled water in parallel with other treatments. The positive control rat group (GII) was administered 30 mg kg−1 indomethacin to induce gastric ulcers. The KF and KF extracts were used individually or together with SP in treating indomethacin-induced gastric ulcerated rat groups. Gastric ulcerated rat’s groups GIII, GIV, GV, GVI, and GVII were orally administered at 30 mg kg−1 rat body weight as total phenolic content (TPC) equivalent from SP, KF, KP, SPF extracts, and Lansoprazole (30 mg kg−1, as reference drug) daily up to 14 days, respectively. The relevant biochemical parameters, antioxidant biomarkers, and histopathological examination were examined. Remarkably, treating rats with SP, KF, KP, and SFP extracts markedly reduced gastric juice and stomach volume expansion induced by indomethacin. The SP significantly retrieved the pH of gastric juice to a regular rate compared to GI. The ulcer index (UI) was significantly attenuated by SP, KF, KP, and SFP administration. The protection index percentage (PI %) was 80.79, 54.51, 66.08, 75.74, and 74.86% in GIII, GIV, GV, GVI, and GVII, respectively. The gastric mucin content was significantly better attenuated by 95.7 in GIII compared to its content in GI. Lansoprazole increased mucin content by 80.3%, which was considerably lower than SP and SFP. SP, KF, KP, SFP, and Lansoprazole improved the reform of gastric mucosal-increased secreted mucus by 95.6, 61.3, 64.8, 103.1, and 80.2% in GIII, GIV, GV, GVI, and GVII, respectively. Interestingly, SFP efficiently increased vit. B12 level by 46.0% compared to other treatments. While Lansoprazole administrating did not significantly attenuate vit. B12 level. The SP and SFP improved iron and Hemoglobin (HB) levels depending on treatment. SP, KF, KP, and SFP significantly decreased the malondialdehyde (MDA) and increased reduced glutathione (GSH) as well as superoxide dismutase (SOD) levels in blood and stomach tissues. The most potent effect was observed with SP, and SFP was even better than Lansoprazole. Histopathologically, treating rats with SP extract showed a marked reduction of gastric damage and severity changes induced by indomethacin. KP was much better than KF in lessening gastric histopathological damages caused by indomethacin. SFP significantly alleviates gastric histopathological alterations. The lansoprazole-treated group (GVII) greatly relieved the gastric histopathological changes and recorded mild focal necrosis and desquamation of the mucosa in addition to mild oedema in the serosal layer. In conclusion, the presented results proved the antiulcer potential of SP and A. chinensis extracts against an indomethacin-induced gastric ulcer in rats, which may be due to their antioxidant and anti-inflammation efficiency. Thus, these data suggested that SP, KF, KP, and SFP extracts as natural and safe alternatives have a gastroprotective potential against indomethacin-induced gastric ulceration. The antioxidative and anti-inflammatory properties are probable mechanisms.

Identity, Synthesis, and Cytotoxicity of Forchlorfenuron Metabolites in Kiwifruit.

Forchlorfenuron (CPPU) is a plant growth regulator widely used in kiwifruit production. Although research on the toxicological and environmental effects of CPPU is well-established, the nature and toxicological properties of its metabolites are much less well-known. Using high resolution mass spectrometry and nuclear magnetic resonance, the CPPU previously unidentified metabolites in Xuxiang and Jinyan kiwifruit were identified as N-(2-chloro-4-pyridinyl)-N'-(2-hydroxy-4-methoxyphenyl)-urea (metabolite 1) and N-phenyl-N'-4-pyridinylurea (metabolite 2, CAS: 1932-35-0). Their structures were confirmed by synthesis (metabolite 1) and by comparison with a commercial standard (metabolite 2). Quantitative studies demonstrate that CPPU and its metabolites are mainly retained in the kiwifruit peel, while the content is dependent on the nature of the peel surface, with the smoother peel of Jinyan kiwifruit retaining smaller amounts of the compound. Cell viability experiments in Caco2 and Lo2 cells show that the metabolites may have a lower cytotoxicity compared to the parent compound CPPU.

Enhanced functionality of green synthesized sulfur nanoparticles using kiwifruit (Actinidia deliciosa) peel polyphenols as capping agents

Enhanced functionality of green synthesized sulfur nanoparticles using kiwifruit (Actinidia deliciosa) peel polyphenols as capping agents

Non-Equilibrium Multi-Ion Biosorption Isotherms for Removal of Heavy Metals from Drinking Water

Biosorption isotherms define the relationship between biosorption capacity of the biosorbent and the equilibrium concentration of the ions in solution, at a constant temperature. Experiments are routinely performed under near-equilibrium because it is impossible to determine the exact time at which equilibrium was attained. A novel attempt to study multi-ion biosorption in non-equilibrium conditions has been made, based on the Probability Isotherm theory. Materials and Methods: Probability Isotherm theory was examined with cucumber and kiwifruit peel beads which are reported to be efficient biosorbents. The peels were incubated in a cocktail of seven ions (As, Cd, Cr, Cu, Hg, Pb and Ni) at the same initial concentration (0.1- 15 mgL-1) and four different temperatures (25-55°C). Non-equilibrium biosorption data were modeled by Langmuir isotherm model. Data were analyzed using a one-way ANOVA coupled with a Bonferroni post-hoc test on GraphPad Prism 8 software. Cd and Ni ions showed the most well-defined trends with Langmuir isotherm model. The binding of ions was physico-chemical with simultaneously occurring physisorption and tchemisorption reactions. Conclusions: Probability Isotherm theory can be applied to multi-ion biosorption in non-equilibrium conditions. The behavior of each ion is unique and no two biosorption systems are alike.

Facile synthesis of ZnO nanoparticles by Actinidia deliciosa fruit peel extract: Bactericidal, anticancer and detoxification properties

Synthesis of nanoparticles by eco-friendly method pulled an extensive concern worldwide due its biocompatibility and wide range of applications as catalysts, microbicidal agents, cancer treatment, sensors etc. Though different chemical methods available for preparation of ZnO nanoparticles, synthesis by utilizing plant material is an excellent substitute and green method as well. The present study describes preparation of ZnO nanoparticles by low-cost green synthetic way using Actinidia deliciosa (kiwi) fruit peel extract and its excellent biological and catalytic properties. The synthesized nanoparticles were well characterized by UV visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy-dispersive X-ray spectroscopy (EDAX). The bactericidal activity of the ZnO nanoparticles was determined by using Staphylococcus aureus (S. aureus), while mechanism of cell death was studied by SEM images. Superior anticancer activity was also observed in inhibiting the colon cancer cells (HCT116) by the ZnO nanoparticles. In addition, ZnO nanoparticles showed efficient photocatalytic activity towards degradation of p-bromophenol, about 96.3% within 120 min. Furthermore, phytotoxicity of the intermediate products was analyzed using Vigna radiata (V. radiata) as a model plant. About 8.0% of germination index (GI) was observed in pure p-BP while it increased to 82.3%, and exhibited that the detoxification of p-BP was attained after 120 min of degradation. Thus, the present study demonstrates ZnO nanoparticles prepared from simple, rapid, inexpensive, eco-friendly and efficient green method gives alternative root for biomedicine and wastewater treatment technologies.

Physicochemical, nutritional, and bioactive properties of pulp and peel from 15 kiwifruit cultivars

Kiwifruit, as a source of vitamin C and phenolic profiles, is well known for its nutrition and health benefits. To select varieties suitable for deep processing and better utilise kiwifruit by-products, a comprehensive characterisation of 15 kiwifruit cultivars was performed. The characterisation included physicochemical and nutritional properties, as well as the phenolic compounds of each pulp and peel. The results revealed that kiwifruit exhibited differences in quality by variety, ‘Hongyang’ and ‘Yate’ may be more suitable for fresh consumption due to their high sugar-to-acid ratio (10.39 and 10.27, respectively). All cultivars contained fructose (13.06–33.77 mg/g) and glucose (13.67–36.6 mg/g) as the dominant sugars. Also, kiwifruits had high vitamin C content (47.24–171.64 mg/100 g) and total phenolics (75.43–316.14 mg GAE/100 g FW). Quinic acid (4.78–19.85 mg/g) and citric acid (4.22–11.36 mg/g) were the main organic acids. Most kiwifruit peel samples contained higher amounts of phenolic compounds, especially gallic acid, p-hydroxybenzoic acid, epicatechin, and catechin, than did pulp. A hierarchical cluster analysis revealed that the ‘Miliang’, ‘Allison’, ‘Kuimi’, ‘Jinkui’, and ‘Jinxiang’ cultivars have potential for the development of high value-added antioxidant polyphenol products.

Antioxidant properties of watermelon (Citrullus lanatus) rind pectin films containing kiwifruit (Actinidia chinensis) peel extract and their application as chicken thigh packaging

This study aimed to develop biodegradable watermelon rind pectin (WRP) films containing 0.5, 1.0, and 1.5 % kiwifruit peel extract (KPE) and investigate their mechanical properties, water vapor permeability, optical properties, and microstructure along with their antioxidant effects on chicken thigh during storage. The obtained WRP films showed an excellent tensile strength and Young’s modulus compared to those of the pectin-based other films. With the increase in KPE concentration, the opacity, elongation at break, and water vapor permeability of the films increased, whereas the rigidity of the films decreased. Moreover, after 9 days of storage, the contents of peroxides and thiobarbituric acid reactive substances in the chicken thigh wrapped with the WRP film containing KPE were lower than those in the unwrapped samples. These results indicate that WRP films containing 1.5 % KPE are potential functional packaging materials that can retard the lipid oxidation in foods.

Preparation and characterization of bacterial cellulose produced from fruit and vegetable peels by Komagataeibacter hansenii GA2016

This study focused on the investigation of bacterial cellulose production potency of some fruit and vegetable peels (cucumber, melon, kiwifruit, tomato, apple, quince and pomegranate) with Komagataeibacter hansenii GA2016. Fruit and vegetable peels were hydrolyzed, used for bacterial cellulose (BC) production and their chemical, physical, thermal and structural features were compared to BC from Hestrin–Schramm medium (HSBC) and plant cellulose (CP). Except for pomegranate peel hydrolysate, all the fruit and vegetable peel hydrolysates supplied to K. hansenii GA2016 supported the BC production. Among the fruit and vegetable peel hydrolysates, the highest BC production was observed in kiwifruit peel hydrolysate (11.53%), while the lowest production was observed in apple peel hydrolysate (1.54%). Water-holding capacities of the BCs were ranged from 627.50% to 928.79% and higher than HSBC (609.30%), average fiber diameters were ranged from 47.64 nm to 61.11 nm and thinner than HSBC (74.29) and CP (10,420 nm), crystallinities were ranged from 80.27% to 92.96%, thermal capacities BCs were higher than HSBC and CP. For the BC productions, utilization of the fruit and vegetable peels as the sole nutrient source could reduce the production costs and among the polysaccharides, increase the use of BC in industry.

Evaluation the efficacy of clove, sage and kiwifruit peels extracts as natural preservatives for fish fingers

The antioxidant and antimicrobial potential of clove, Sage and kiwifruit peel extracts as well as their mixture, were evaluated as natural preservatives for fish fingers. The treated samples with the mix (1:1:1) of aqueous extracts showed results superior to that of the synthetic antioxidants. Values of thiobarbituric acid reactive substances (TBARS) recorded with the mix at 0.10%, 0.25% and 0.50% were 0.97, 0.62 and 0.53 mg MDA/kg respectively, compared to negative control and BHT (Butylated Hydroxytoluene) as a positive control which recorded 2.12 and 1.52 mg MDA/kg at the 30th day of storage. The microbial analysis emphasized a superior preservation power of the plant extract mixture. The total microbial count in treated samples with plant extracts mix at 0.1%, 0.25% and 0.5% were 3.7 × 103, 5.7 × 102 and 3.3 × 102 cfu/g compared to the negative and positive control (BHT) which showed the total microbial count 1.8 × 104 and 5.5 × 103 cfu/g respectively, at the 30th day of storage. These findings emphasized the powerful effect of the mixture of plant extracts at the level of 0.5% to extend the shelf life of fish fingers during storage period up to 30 days under cold storage conditions (4 ± 1 °C). These findings suggest that the extract mix may serve as an alternative choice to use as a food additive extending the shelf life of food products.