Peel Hardness Research Articles

Nondestructive detection of kiwifruit textural characteristic based on near infrared hyperspectral imaging technology

ABSTRACT The nondestructive detection of kiwifruit texture has become an important necessity that influences kiwifruit economic efficiency and consumer recognition of the kiwifruit. This study investigated the feasibility of using hyperspectral imaging technology to identify textural characteristics of kiwifruit, and to establish the model with best performance. Firstly, a near-infrared hyperspectral online grading system (1000–2500 nm) was constructed to acquire spectral images. Textural characteristics were measured via three different textural analysis tests: textural profile analysis, puncture test, and shear test. Then, samples were divided into a calibration set and a prediction set based on rank sampling at a ratio of 3:1. Mean centralization, standard normal variate, and multiplicative scatter correction methods were applied to pre-process obtained spectra. Finally, the partial least squares method was used to establish prediction models of kiwifruit textural characteristics. The models of hardness1, chewiness, resilience, peel hardness, average hardness, and corrected hardness achieved good performance. Both the correlation coefficients of calibration (rc) and prediction (rp) values exceeded 0.9. The difference between the root mean square error (RMSE) of calibration and prediction was small, and the ratio of prediction to deviation (RPD) value exceeded 2, which was used to predict kiwifruit quality. However, the model of average shear force had a low accuracy with an RPD of 1.680 and the model of shear force also had an RPD below 1.5 and a low RMSE. The results showed that near-infrared hyperspectral imaging technique can be used as a nondestructive method for the textural characteristics kiwifruit.

Chemometric Comparison and Classification of 22 Apple Genotypes Based on Texture Analysis and Physico-Chemical Quality Attributes

The large number of cultivars belonging to the cultivated apple (Malus × domestica Borkh.) reflects an extremely wide range of variability, including for fruit quality traits. To evaluate some characteristics of fruit quality, 22 apple genotypes were selected from a collection of germplasms containing more than 600 accessions, based on different considerations, including the use of fruits (dessert, cooking, processing, juice, cider, multipurpose). The mean water content of the studied apple genotypes was 85.05%, with a coefficient of variation (CV) of 2.74%; the mean ash content was 2.32% with a CV of 22.1%, and the mean total soluble solids was 16.22% with a CV of 17.78%, indicating a relatively small difference between genotypes for these indices. On the contrary, relatively large differences were registered between genotypes for fruit weight, volume, and titratable acidity with means of 119.52 g, 155 mL, and 0.55% malic acid, and CVs of 35.17%, 34.58%, and 54.3%, respectively. The results showed that peel hardness varied between 3.80 and 13.69 N, the toughness between 0.2 and 1.07 mm, the flesh hardness between 0.97 and 4.76 N, and the hardness work between 6.88 and 27.84 mJ. The current study can emphasize the possibility of choosing the appropriate apple cultivars to cross in the breeding process and how future strategies can help apple breeders select breeding parents, which are essential key steps when breeding new apple cultivars. In addition, multivariate analysis has proven to be a useful tool in assessing the relationships between Malus genetic resources.

Genome-Wide Analysis of the Peroxidase Gene Family and Verification of Lignin Synthesis-Related Genes in Watermelon.

Watermelon (Citrullus lanatus) is an important horticultural crop worldwide, but peel cracking caused by peel hardness severely decreases its quality. Lignification is one of the important functions of class III peroxidase (PRX), and its accumulation in the plant cell wall leads to cell thickening and wood hardening. For in-depth physiological and genetical understanding, we studied the relationship between peel hardness and lignin accumulation and the role of PRXs affecting peel lignin biosynthesis using genome-wide bioinformatics analysis. The obtained results showed that lignin accumulation gradually increased to form the peel stone cell structure, and tissue lignification led to peel hardness. A total of 79 ClPRXs (class III) were identified using bioinformatics analysis, which were widely distributed on 11 chromosomes. The constructed phylogenetics indicated that ClPRXs were divided into seven groups and eleven subclasses, and gene members of each group had highly conserved intron structures. Repeated pattern analysis showed that deletion and replication events occurred during the process of ClPRX amplification. However, in the whole-protein sequence alignment analysis, high homology was not observed, although all contained four conserved functional sites. Repeated pattern analysis showed that deletion and replication events occurred during ClPRXs’ amplification process. The prediction of the promoter cis-acting element and qRT-PCR analysis in four tissues (leaf, petiole, stem, and peel) showed different expression patterns for tissue specificity, abiotic stress, and hormone response by providing a genetic basis of the ClPRX gene family involved in a variety of physiological processes in plants. To our knowledge, we for the first time report the key roles of two ClPRXs in watermelon peel lignin synthesis. In conclusion, the extensive data collected in this study can be used for additional functional analysis of ClPRXs in watermelon growth and development and hormone and abiotic stress response.

The Influence of Fertilization on Pomegranate Susceptibility to Infestation by Ectomyelois ceratoniae

ABSTRACT Carob moth, Ectomyelois ceratoniae Zell (Lep.: Pyralidae), is the most important pest in Iranian pomegranate orchards and imposes tremendous annual economic loss to the pomegranate producers. A two-year study was conducted to investigate the effects of the utilization of different fertilizers on the carob moth infestation of pomegranate cv. ‘Bajestani’. Fertilizer programs significantly affected fruit infestation. The highest infestation rate was recorded in unfertilized plants (38.07%, 31.44% in the first and the second years, respectively). Among different treatments, chemical and humic fulvic-containing fertilizers proved to be the most efficient treatments for controlling carob moth. A Significant correlation was observed between carob moth infestation and various fruit and tree-related attributes. The peel hardness and its hardness-associated nutrients (Ca, K and Si), as well as total phenolic content of fruit juice, were among the factors that showed a high negative correlation with carob moth infestation. According to our results, a combination of organic and Si, Ca, and K-containing fertilizers has great practical potential in the management of pomegranate orchards to reduce the carob moth damages.

Interaction Among Peel Hardness, Fruit-Age and Gibberellic Acid on Infestation Susceptibility of Citrus Fruits by Peach Fruit Fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae)

Influence of gibberellic acid (GA3) on susceptibility of citrus fruits to infestation by Bactrocera zonata was studied under field conditions. The susceptibility of navel orange and mandarin fruits to infestation by PFF was affected firstly by GA3 treatments in a dose-dependent manner and secondly by host type. GA3 treatment was more effective on mandarin than navel orange in terms of rate of false punctures and egg-laying density, whereas it showed more effect on the true puncture numbers of navel oranges than mandarins. The results also showed that fruit infestation parameters were inversely proportional to fruit peel hardness. Fruit peel hardness was GA3 dose-dependent, with significant differences between host types, as well as among GA3 concentrations, with higher values on navel orange than mandarin. Results also revealed that date (progress of fruit age) had a weak effect on both infestation parameters by PFF, and fruit peel hardness. The study provides clear evidence that exogenous application of GA3 could be incorporated in IPM programmes for citrus to decrease the infestation rates by PFF.

Symptomatology of Citrus mosaic sadwavirus (CiMV) in Some Citrus Cultivars and Effect of CiMV Infection on Citrus Fruit Quality.

Citrus mosaic sadwavirus (CiMV) is a closely related virus with the Satsuma dwarf virus (SDV) along with Navel orange infectious mottling virus (NIMV), Natsudaidai dwarf virus (NDV), and Hyugagatsu virus (HV). The present study found that the typical symptoms of CiMV-infected citrus fruits include the appearance of dark blue speckles or ringspots on fruit rinds and the browning of oil glands in the spots as rind coloring began. As rind coloring progressed, the spots gradually faded, whereas the browning of the oil glands worsened to the point that the tissues surrounding the oil glands became necrotic. In very early satsuma mandarins (Citrus unshiu ‘Miyamoto Wase’) and ‘Setoka’ cultivar (C. hybrid ‘Setoka’) of late-maturity citrus, the symptomatic fruits were eventually dropped. And in early satsuma mandarin (C. unshiu ‘Miyakawa Wase’), the peel hardness of the virus-infected fruit (1,618.3 ± 305.5, g-force) was more than twice as hard as that of the healthy fruit (636.5 ± 39.1, g-force). The ratio of flesh weight to total fruit weight was higher for the healthy fruit (77.3 ± 1.7%) than for the infected fruit (70.7 ± 0.6) and peel puffing was more severe in the infected fruit (2.9 ± 0.4 mm) than in the healthy fruit (0.9 ± 0.2 mm). The soluble solids content in infected citrus fruits was less values than the healthy fruit by 0.5–1.5 °Brix. These findings reveal that CiMV infection on citrus trees reduces the fruit quality of citrus.

Shelf life prediction model of postharvest table grape using optimized radial basis function (RBF) neural network

Purpose The purpose of this paper is to develop a common remaining shelf life prediction model that is generally applicable for postharvest table grape using an optimized radial basis function (RBF) neural network to achieve more accurate prediction than the current shelf life (SL) prediction methods. Design/methodology/approach First, the final indicators (storage temperature, relative humidity, sensory average score, peel hardness, soluble solids content, weight loss rate, rotting rate, fragmentation rate and color difference) affecting SL were determined by the correlation and significance analysis. Then using the analytic hierarchy process (AHP) to calculate the weight of each indicator and determine the end of SL under different storage conditions. Subsequently, the structure of the RBF network redesigned was 9-11-1. Ultimately, the membership degree of Fuzzy clustering (fuzzy c-means) was adopted to optimize the center and width of the RBF network by using the training data. Findings The results show that this method has the highest prediction accuracy compared to the current the kinetic–Arrhenius model, back propagation (BP) network and RBF network. The maximum absolute error is 1.877, the maximum relative error (RE) is 0.184, and the adjusted R2 is 0.911. The prediction accuracy of the kinetic–Arrhenius model is the worst. The RBF network has a better prediction accuracy than the BP network. For robustness, the adjusted R2 are 0.853 and 0.886 of Italian grape and Red Globe grape, respectively, and the fitting degree are the highest among all methods, which proves that the optimized method is applicable for accurate SL prediction of different table grape varieties. Originality/value This study not only provides a new way for the prediction of SL of different grape varieties, but also provides a reference for the quality and safety management of table grape during storage. Maybe it has a further research significance for the application of RBF neural network in the SL prediction of other fresh foods.

The difference of sensory qualities of apple fruit among eight cultivated varieties

The differences of sensory qualities among 8 apple varieties were studied by the properties, including moisture content, color difference and texture using color difference meter and texture analyser. These three parameters had a significant effect on the sensory edible qualities of apple. The results showed that, there were great differences on fruit sensory qualities among 8 cultivated apple varieties. Water content of Ralls was the highest; the moisture contents of Orin and Indo were lower. Golden Delicious in color difference was clearly distinguished from other varieties. The hue angles of Golden Delicious, Orin and Indo all showed negative values, while other varieties showed positive values. The chromas of Golden Delicious and Indo were higher than others. In terms of texture, for Ralls, Wangshanhong, Orin and Indo, both fruit flesh hardness and peel hardness were higher, while the two indexes of Gloden Delicious were lower.

Effect of different sanitizers on the microbial load and selected quality parameters of “chile de árbol” pepper (Capsicum frutescens L.) fruit

The aim of this work was to evaluate the effectiveness of different substances used as sanitizers for “chile de árbol” (Capsicum frutescens L.) fruit by means of their effect on microbial load as well as on fruit physicochemical and sensory properties. Sodium hypochlorite (100–10,000mgL−1), hydrogen peroxide (5%), ethanol (70%), nisin (125mgL−1), and a commercial lineal anionic surfactant (2%) were used to sanitize pepper fruit. Different exposure times were evaluated for selected sanitizers. Ratios of 1:10 of fruit- solutions were utilized for the sanitization processes. After sanitization, microbiological analyses were performed (total mesophilic aerobic bacteria (TMAB), lactic acid bacteria (LAB), molds, and yeasts); in addition, color (L*, a*, b*), texture (peel’s break force and peel's hardness), pH, and titratable acidity were determined on pepper fruits. In addition, a sensory evaluation was performed. Medium (1000 and 2000mgL−1) and high (10,000mgL−1) sodium hypochlorite concentrations reduced about 2 log10 cycles of TMAB. Molds only were reduced when high concentrations of sodium hypochlorite were used. The most effective sanitizer was ethanol, reducing 4.7 log10 of TMAB, 4.2 log10 of LAB, 2.5 log10 of molds, and 2.7 log10 cycles of yeasts when exposure time was 120min, and final counts were <100CFUg−1 for TMAB, and <10CFUg−1 for LAB, molds, and yeasts. Hydrogen peroxide generated the greatest losses of greenness and texture of treated pepper fruit. The pH increased (ΔpH=0.2) when high concentrations of sodium hypochlorite were used. The sanitization processes did not affect lightness and titratable acidity. Judges detected losses in greenness of pepper fruits sanitized with hydrogen peroxide (5%, 30 or 120min), sodium hypochlorite (10,000mgL−1, 120min), or ethanol (70%, 30min); losses in firmness for pepper fruits treated with hydrogen peroxide (5%, 30min) or nisin (125mgL−1, 120min); but noticed increments (p<0.05) of peppers’ pungent smell sanitized with hydrogen peroxide (5%, 30 or 120min) and sodium hypochlorite (10,000mgL−1, 120min). Peppers’ brightness did not change (p>0.05) after treatments.

Effect of Zn and NAA co-treatment on the occurrence of creasing fruit and the peel development of ‘Shatangju’ mandarin

‘Shatangju’ mandarin creasing results is serious economic loss in many ‘Shatangju’ mandarin orchards. Based on developing accurate preventive strategies for creasing fruit, the creasing of eight-year-old ‘Shatangju’ (Citrus reticulata Blanco cv. Shatangju) onto Poncirus trifoliate (L.) rootstock was investigated. It was treated twice with either Zn or Zn+NAA application in the fruit enlargement stage (18th and 27th of May, 2011), and Zn+NAA (18th and 28th of May, 2012), respectively. The Zn and Zn+NAA treatments at the fruit enlargement stage of ‘Shatangju’ significantly enhanced the levels of IAA, GA3, and tryptophan in the early peel development stage, promoted the growth and division of cells, decreased the range of peel hardness variation during fruit development, reduced creasing abnormalities in peel tissue, especially in albedo, postponed the peel thickness transition time of peel development, and significantly lowered the creasing fruit rate and cumulative abscission rate of ‘Shatangju’ mandarin. Compared with the control and Zn treatment, Zn+NAA treatment could be recommended in the fruit enlargement stage as a cultivation technique to lower the creasing fruit rate of Shatangju mandarin.

Microwave Technology Applied in Post-Harvest Treatments of Cereals and Legumes

For agricultural purposes microwave heating is an emerging technology today successfully applied in postharvest disinfestation treatments of many agricultural products, such as cereals and legumes, susceptible of degradation due to the presence of natural infesting fauna. Microwave irradiation is proposed as an effective alternative to chemical methods of disinfestation which can be characterized by severe side effects. Extensive studies focused on disinfestation treatments assisted by microwave have proved their effectiveness. Overall goal of the present research is to point out correlations between thermo-physic properties and irradiation conditions (power, time to exposure, load configuration) to stabilize cereals and legumes in short time without damages of structures and nutritive features. In this work, two kinds of agro-foods, weak wheat and beans, were undergone to microwave heating and several physical properties, devoted to control structural possible changes, were investigated on irradiated samples. The achieved results show that the applied irradiation protocol globally does not affect water uptake phenomena in swelling and cooking treatments, peel hardness and germination capability of seeds.

Prediction of hardness development in mangosteen peel using NIR spectroscopy during low temperature storage

Peel hardening, due to loss of moisture during low temperature storage, is a prevalent problem in mangosteen. This research develops a model for predicting peel hardening in mangosteen, using a correlation with moisture content as determined by NIR spectroscopy. Mangosteen fruit were stored and their NIR reflectance, moisture content, and peel hardness were measured over time. Additional fruit was also stored for monitoring, and their NIR reflectance measured. Peel hardness of mangosteen in storage initially decreased, and then increased from the middle to the end of the storage period. Changes in peel hardness, based on moisture content over the 28 days of storage at 13 °C can be predicted, as well as for the 16 days storage at room temperature.

Texture and antioxidant evolution of naturally green table olives as affected by different sodium chloride brine concentrations

The results on the evolution of the texture and antioxidant activity during the processing of naturally fermented green olives are reported in the present study. The olives were brined with two different NaCl concentrations, 4 and 7%. A puncture test and a texture profile analysis (TPA) test were carried out to evaluate texture, while the antioxidant activity was assessed in consideration of the loss of absorbance of a stable radical upon reaction with a polyphenolic olive extract. The puncture test revealed both an increase and decrease in peel and flesh hardness, respectively. The olives processed with 7% NaCl concentration showed higher peel hardness than olives brined with 4% salt. The texture profile analysis did not reveal any difference between the two salt concentrations used, but showed a decrease in the value of all parameters after 30 days of brining. The antioxidant activity of the polyphenolic extract decreased significantly during processing, with a major loss after the first 30 days of processing and was higher in the 7% brined olives, than the sample treated with 4% NaCl.

Climatic conditions affect the texture and colour of Cavendish bananas (Grande Naine cultivar)

Relationships between natural production conditions (soil and climate) and physical fruit traits (texture and colour) were studied in Martinique to fuel discussions on creating a label for bananas from the French West Indies. Bananas produced at six sites, under very different conditions, during three different periods of the year, were harvested at the same temperature sum and ripened under identical conditions. The peel of green bananas harvested during the hot humid season was not as hard as that of bananas harvested during the cool dry season. In ripe bananas, an increasing correlation was noted between the rainfall level and fruit firmness ( R = 0.88) and peel hardness ( R = 0.80). This correlation could explain why bananas produced during the dry season were less firm and, conversely, those produced in highland areas, where rainfall is highest, were firmer. In ripe bananas, a decreasing correlation was also noted between the mean daily temperature and the fruit yellowness ( R = 0.84). This interaction could be responsible for the yellower colour of mountain banana pulp and of bananas harvested during the coolest seasons. The green life of bananas harvested during the hot humid season was shorter than that of bananas harvested during the dry and intermediate seasons.

IMPROVEMENT OF BANANA GROWING CONDITIONS WITH THE KATRYX® BAG

Banana growers commonly use blue sleeves to protect the bunches during fruit growth. The Katryx(R) bag is a transparent sleeve with specific UVb and IR permeability properties, particularly a 30 % IR permeability reduction. This three-layer product was developed and patented by the Plastibana company, to allow better light and temperature conditions for banana growth. The effects of Katryx(R) and blue sleeves on the inside microclimate and on fruit quality were investigated. When using a frame to simulate the bunch, it was found that the Katryx(R) sleeve had a buffer effect with high temperatures. Thermal variations between night and day were thus limited; the inside temperature was kept around the theoretical optimum growth value in the West Indies, which varies between 29 and 30'C. When using the Katryx(R) sleeve, an increase in light quantity and a modification in light quality were also observed and, therefore, an increase in the photothermal coefficient. Banana plants ('Cavendish' cv 'Grande Naine') were used to investigate the effect of Katryx(k and blue sleeves on fruit growth. Katryx(R) covering increased fruit firmness and peel hardness, as well as fruit length and average grade (+2 to 8%), depending on the environmental conditions and on the position of the hand. (Resume d'auteur)