Sanitizing fruit and vegetables with gaseous ozone promotes food safety, marketability, and extended postharvest shelf-life. Ozone is a self-decomposing gas that disinfects and neutralizes microorganisms on packing equipment, water, and produce surfaces. The USDA permits ozone use in "organic" products. Ozone is produced on-site through a corona discharge mechanism using commercially gaseous ozone generators. This study studied gaseous ozone application on peaches, ranging from 0.5 - 5 ppm compared to control storage (CS). Gaseous ozone applications are known for postharvest spoilage vulnerability to assess microbial load reduction and defense against diseases like brown rot and gray mold. Investigated varieties (July Prince, Scarlet Prince, August Lady, and O’Henry), stored under controlled conditions of 35°F (1.7°C) at 90% relative humidity, revealed that 5 ppm ozone resulted in high decay (~40-42%). However, 0.5 ppm treatment maintained peach quality comparable to controls, with decay rates between 3.5 to 7%. Notably, peaches treated with 0.5 ppm also exhibited higher firmness than the other treatments and unaffected visual quality up to the 28th storage day. The findings suggest ozone’s potential to enhance postharvest practices, highlighting its efficiency, and could serve as an effective counteract treatment for decay incidence that will benefit the peach industry.
The compression test is the standard procedure to measure fruit firmness in sweet cherries. Nevertheless, this measurement is not always well correlated with perceived texture by buyers and consumers; therefore, the cherry industry needs a better way to grade fruit firmness. Hyperspectral information was correlated to fruit firmness as an alternative to compression values. ‘Skeena’ cherries, grown under commercial conditions in central Washington, were harvested in 2023 and stored for 30 days at 0-1oC. Compression measurements (at 20oC; FirmTech 2, BioWorks Inc) were carried out at harvest and 15 and 30 days into storage. Immediately after these measurements, hyperspectral images from the fruit (n=1030) were taken using a Vi-NIR camera (Headwall Photonics). The comparison between low (< 303 mm/g), medium (303-374 mm/g), and high firmness (>374 mm/g) groups did not yield any spectral differences. Despite this, iPLS wavelength selection showed bands > 800 nm suitable to model these compression groups. On the other hand, Neural Network, Random Forest, and PLS models were not able to predict compression values (regression) or firmness groups (classification). Furthermore, the regression models tested did not have coefficients of determination higher than 0.42 with root mean squared errors of 40 mm/g for compression values with the training dataset. Classification models achieved total accuracies of around 65-70 % and had problems distinguishing between low-medium and medium-high compression values. All models showed poor performance when tested with an independent data set. These results are in contrast to previous reports, which used a lower fruit number, reinforcing the challenge of tailoring a non-destructive technique to predict firmness through compression values in sweet cherries, a highly variable phenotypic characteristic.
Blueberry producers in the United States are facing high input costs and labor shortages, which have led them to mechanize several areas of blueberry production, particularly harvesting. Even though the use of machine harvesters is advantageous to producers and new technologies have been developed in recent years, several parts of the process still require improvements. One of the issues caused by the adoption of mechanical harvesting is increased harvest intervals, due to the high capital expenses associated with the purchase of such machinery that in turn leads to limited availability of harvesters to perform the harvest in a timely fashion. This trend may compromise berry quality, particularly in the Southeastern United States. Firmness is a critical factor in determining consumer preference, shelf life, and market value of fresh blueberries. The postharvest quality of blueberries is influenced by various factors, including genotype, postharvest handling, and harvest conditions such as harvest intervals. This study aimed to investigate the impact of different harvest-regimes on fruit quality and storability of ‘Brightwell’ blueberries. The experiment was conducted at the Alma Blueberry Research Farm, with a randomized complete block design. Fruit were hand-harvested at different intervals: T1: every 2 days, T2: every 3 days, and T3: every 7 days. Each treatment was replicated four times, resulting in nine harvests across all treatments. Following the harvest, the berries were sorted for defects, packed in clamshells, and stored at 1°C (34°F) and 85% relative humidity. Fruit quality parameters: firmness, fruit size, color, total soluble solids (TSS), titratable acidity, and fruit rot evaluation were evaluated at four different intervals: 1, 7, 14, and 21 days after harvest. Preliminary results indicate that fruit from the second and third harvests, T1 and T2 exhibited higher firmness readings at harvest compared to T3. Throughout the storage period, the firmness of the fruit was consistently higher in T2 compared to other treatments. A bigger fruit size was obtained at the first harvest of all treatments which declined after 14 days of storage in all three treatments. At the second harvest, T2 had the highest TSS but after 21 days of storage, TSS declined and T1 had the highest TSS after 21 days of storage in all three harvests. Additionally, T3 had a higher fruit rot incidence, and wet, sunken berries in the second and third harvests. So, a harvest interval of less than 7 days is recommended to maintain the fruit quality.
Interest in producing elderberry (Sambucus nigra ssp. canadensis) fruit in North America has increased in recent years, including the subtropical climate of Florida. The fruit contain high amounts of antioxidants in both the juice and solid fractions and are processed into a wide variety of products. Fruit grow in clusters (cymes) of 500 or more fruit (1-2 mm diameter) each, and typically ripen at different rates, depending upon when the flowers were fertilized, the variety/selection and weather conditions. This non-uniform ripening from green to deep purple challenges growers, since unripe fruit must be removed. Delaying cyme harvest until all fruit ripen is not feasible since overripe fruit abscise before unripe fruit ripen. Fruit are typically destemmed from the cymes the day of harvest, either manually or with mechanized systems. Destemming can cause significant loss of salable product as the fruit are often crushed, releasing juice. In a series of tests, we investigated the potential to promote uniform ripening and detachment of elderberry fruit by postharvest exposure to gaseous ethylene, commercially used to initiate ripening in climacteric fruit crops. At a commercial farm in Chiefland, Florida, small segments (approximately 30 fruit each) were cut from cymes with 75% ripe fruit from three elderberry genotypes (DNS11, DNS23 and DNS36). The samples were returned to the UF Postharvest Laboratory that day, divided into two treatment groups ( /- 100 ppm ethylene) and sealed in glass jars (n=3; 3 segments/jar) at 22 °C/95% relative humidity. Jars were opened after 24, 48 and 72 hr to avoid CO2 accumulation; at each timepoint, one jar was removed and fruit examined; remaining jars were resealed and ethylene concentration was reestablished. Exposure to ethylene significantly increased ripe fruit detachment after 24 hr, however partially ripe fruit ripened after 48 hr, irrespective of treatment. Fruit juice content was 46%, pH=5.0. Ethylene did not affect the following parameters, although there were differences in germplasm: soluble solids content (7-14%), total titratable acidity (0.44-0.70%), and total anthocyanin content (8-20 mg · g-1). Attached or detached fruit lost 6-10% weight after 24 hr, whereas stems lost about 50% weight; after 48 hr, shrivel symptoms appeared and weight loss roughly doubled for these same groups. Consideration must be given as to exposure to ethylene for 24 hr for easy fruit removal versus holding for 48 hr for ripening with accompanied higher weight loss and shriveling.
Hardy kiwifruit (Actinidia arguta) is highly sensitive to low temperatures, which can cause chilling injury (CI) as a physiological disorder. Peel surface pitting with black/dark brown spots was developed as CI symptoms in cold-stored hardy kiwifruit. In this study, we performed transcriptomic and lipidomic analyses to elucidate the potential mechanism of CI symptoms in cold-stored hardy kiwifruit. The peel tissues of hardy kiwifruit were collected after harvest (HV) and after cold storage; pitted peel tissues from CI-damaged fruit (PT) and healthy peel tissues from CI-unaffected fruit (HT) were also collected. Transcriptomic analysis identified 10,612 differential expressed genes (DEGs) between HV and HT tissues, and 3,206 DEGs were detected between HT and PT tissues. Among the 3,206 DEGs, 1,322 transcripts were up-regulated in HT tissues, while 1,874 transcripts were up-regulated in PT tissues. The KEGG pathway enriched by up-regulated DEGs in HT indicated protein modification, L-valine degradation, and polyol metabolism, while up-regulated DEGs in PT enriched alkaloid biosynthesis, protein modification, and lipid metabolism. In lipidomics analysis, a total of 101 lipids clustered into 14 subgroups were detected in peel tissues of cold-stored hardy kiwifruit. Based on the results of VIP scores (> 1.5), the levels of triacylglycerol (TAG) 54:8, TAG 54:9, phosphatidylcholine (PC) 36:4, PC 34:2, PC 36:5, PC 34:3, and TAG 54:7 were higher in PT tissues, but the levels of phosphatidylethanolamine (PE) 36:2, phosphatidylserine (PS) 38:3, PS 36:0, PC 36:1, PE 34:1, and PE 36:1, were higher in HT tissues, compared with the other tissues. Therefore, the results indicated that the CI symptoms in cold-stored hardy kiwifruit would be derived from integrated transcriptomic and lipidomic results.
The ripening and senescence of fresh fruit and vegetables are inevitable during storage, transportation, and sale, which will reduce their marketability and cause substantial economic losses. The infection of pathogenic microorganisms can also lead to food safety problems. Plant essential oils are considered a promising strategy to preserve fresh produce. However, their application is limited by several aspects, including high volatility, low solubility, off flavor, etc. Encapsulation technology has emerged as a promising solution to alleviate these limitations. Nanoencapsulation is a delivery system for bioactive compounds that is usually employed to support the stability of the agents, maximize their retention, and control the release of the compounds at the target locations. A nanoemulsion composed of carvacrol and β-cyclodextrin was prepared by an ultrasound-mediated method, and the encapsulation process was conducted using a Buchi® Nano Spray Dryer B-90. The inclusion complex powder was collected and filled to air-permeable sachets. The sachets were then fixed inside commercial clamshells containing limes to simulate shelf-life. Fruit quality and total microbial population were analyzed. The results showed that the dimensions of spray-dried powders were primarily at nanoscale. The encapsulation process did not affect the antimicrobial and antioxidant activities of carvacrol. The nanocapsules prolonged the release of carvacrol. It effectively delayed the rapid color deterioration of limes without causing phytotoxicity, and maintained lime quality with higher firmness and lower weight loss. Free carvacrol and carvacrol/β-cyclodextrin treatments significantly reduced the growth of P. digitatum and total bacteria on fruit peel and inside of the wounds. However, the GC-MS results showed carvacrol residue detected from free carvacrol-treated fruit, but not from the carvacrol/β-cyclodextrin-treated fruit. The results indicate that nano-encapsulated carvacrol/β-cyclodextrin inclusion complexes can be applied as an effective strategy to preserve postharvest produce. Keywords: Nanoencapsulation, nano spray drying, essential oil, postharvest quality, lime
Sweet potato (Ipomoea batatas L.) is one of the seven major food crops grown worldwide. The optimal storage temperature for sweet potatoes is 12-15℃, and chilling injury occur when it falls below 10℃. The initial symptom of chilling injury in sweet potatoes is difficult to discern in visual judgment and requires checking through a cut-off sections. Therefore, this study intended to develop a non-destructive chilling injury prediction model using VIS/NIR spectroscopy sensors. USB4000 Fiber Optical Spectrometer was used for collecting spectrum data in the wavelength of the visible to near-infrared region (400 nm to 1100 nm), and the average value was used by measuring six areas divided into upper, middle, and lower parts to reduce errors. Firmness, total soluble solids, internal chromaticity, chilling index, and Malondialdehyde (MDA) were measured as reference data, and Partial Least Squares Regression(PLSR) method was used for prediction. To increase the accuracy of the model, the near-infrared spectrum data were preprocessed using the Savitzky–Golay 1st and 2nd derivatives (S–G), standard normal variate (SNV), and multiplicative scattering correction (MSC) methods. Excellent performance models for each preprocessing methods were selected, and as a result of verification through the prediction model, the 'Hogammi' variety showed excellent performance in the preprocessing of Savitzky-Golay 2st derivative in TSS and Malondialdehyde (MDA), and CI index showed the best performance in the processing of SNV. As indicators of chilling injury such as the CI index involve subjective opinions of experimenters, the findings of this study could be used as a fundamental step to develop more objective and accurate chilling injury prediction models by including various internal indicators.
