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Storage information regarding ‘Keepsake’ apple fruit is lacking. The objective of this research was to investigate the postharvest characteristics of ‘Keepsake’ apple (Malus ×domestica Borkh.), which is a parent of ‘Honeycrisp’. Apples were obtained from three orchards in Minnesota in 2022 and 2023, assessed for quality, and stored at 0 to 1 °C or 4 to 5 °C in air. Fruit were tested for firmness, soluble solids content (SSC), and titratable acidity (TA) for up to 6 months in storage. At harvest, fruit from different orchards differed in ground color, firmness, SSC, and titratable acidity. The starch pattern index did not differ among the orchards within a year, but it was greater during the 2023 harvest than during the 2022 harvest. Fruit firmness decreased less rapidly at 0 to 1 °C than at 4 to 5 °C. Changes in SSC with storage varied by orchard, storage temperature, and year. In 2022 to 2023, SSC changes were highly variable, remained the same during storage for fruit from one orchard, increased and then decreased for fruit from another orchard, increased after 1 month of storage, and then remained unchanged thereafter for fruit from the third orchard. In 2023 to 2024, SSC was generally unchanged during storage at 0 to 1 °C, and it increased slightly over time during storage at 4 to 5 °C. Titratable acidity decreased during storage, but there was no difference between storage temperatures. These findings demonstrate the difficulty determining when to harvest ‘Keepsake’ fruit because neither starch pattern index nor ground color is a reliable indicator of ripeness. Growers must rely on experience and fruit redness to determine when to harvest this late-season cultivar. To prolong fruit firmness, growers should store ‘Keepsake’ fruit at 0 to 1 °C rather than at 4 to 5 °C.
We used choice experiments to investigate consumers’ preferences and willingness to pay (WTP) for various apple (Malus ×domestica) varieties. The experiments also asked consumers to evaluate a series of quality attributes by allowing them to taste apples. The choice experiments were conducted in real markets where consumers were making fruit purchases to eliminate any decontextualized biases. The objectives of this study were to determine how much consumers are willing to pay for 13 new and existing apple varieties and learn what quality attributes consumers’ like or dislike in new vs. older apple varieties. Results show that compared with other apple varieties, participants were willing to pay the highest prices for ‘SweeTango®’, followed by ‘Zestar!™’ and ‘Honeycrisp’. Frequent and infrequent buyers were willing to pay significantly different amounts for most of the studied varieties. In addition to WTP estimates, our study also shows what quality attributes consumers consider as improvements compared with existing varieties. Combined with objective measures of these quality attributes, our transdisciplinary study will help apple breeders make more targeted breeding decisions by better understanding what quality attributes consumers like or dislike about the studied varieties.
Anthocyanins are a class of flavonoids that are responsible for pigments in flowers, fruit, and potato periderm. Developing `Norland' potatoes synthesize anthocyanins in periderm tissue when the tubers are mere swollen stolon tips. As the tubers enlarge, anthocyanin accumulation seems to stop, and anthocyanins synthesized early in development seem to be diluted as the tubers enlarge. Expression of dihydroflavonol reductase (DFR) limits anthocyanin synthesis in grape and maize fruit, and in petunia and snapdragon flowers. However, DFR expression in periderm tissue occurred throughout tuber development (Hung et al., 1999). To determine if expression of late anthocyanin pathway genes limit anthocyanin synthesis in developing potato tubers, we performed RNA gel blot analyses. Expression of leucoanthocyanidin dioxygenase and UDP glucose: flavonoid 3-O-glucosyl transferase was observed in swollen stolon tips but not in periderm of later tuber development stages. Surprisingly, expression was also observed in cortex tissue, although that tissue remained white throughout tuber growth.
Determining consumers' preferences and willingness to pay (WTP) for organically grown and locally grown fresh produce is very important for stakeholders because it helps them figure out what type of fresh produce to grow and sell, what to emphasize in marketing efforts, and what are reasonable prices to charge. However, the literature that studies and compares consumers' preference and WTP for both organically and locally grown fresh produce is sparse. The objective of this study was to investigate consumers' WTP for organically grown and locally grown fresh produce and the marketing segmentation of these two types of produce. We combined a hypothetical experiment and nonhypothetical choice mechanism to investigate consumers' WTP for the attributes organic, local, and organic plus local for fresh produce. We found that when real products were used in the hypothetical experiment, the hypothetical bias (the difference between what people say they will pay and what they would actually pay) was not high. We found that consumers' WTP for the organic attribute was about the same as their WTP for the local attribute. Consumers' sociodemographics affected their choice between organically grown and locally grown produce. Furthermore, we found that consumers patronized different retail venues to purchase fresh produce with different attributes. The findings of the research have great importance for fresh produce stakeholders to make correct production and marketing decisions; the findings also contribute to experimental method choice in consumers' WTP research.
To learn what areas should be emphasized in future educational good agricultural practices (GAPs) training efforts, a survey on usage of GAPs was mailed to 855 vegetable growers in Minnesota. We received a 32% response rate and a 43% cooperation rate. Over 65% of respondents reported compliance to proper worker hygiene practices, harvest container and tool sanitization and cleaning, water treatment to reduce the potential for microbial contamination, and protection of growing and stored vegetables from contamination. Small acreages and a diverse array of vegetables are typical characteristics of the majority of Minnesota vegetable farms. Seventy-seven percent of respondents farmed 15 acres or less. Most farms grew 10 or more different vegetable crops, and farmers markets, u-pick operations, and roadside stands were the most common marketing outlets. Overall responses to this study indicated that farmers currently believe they adhere to many recommended food safety best practices, but are lagging in key areas such as treating wash and processing water, taking measures to keep animals out of production fields, and cleaning and disinfecting harvesting tools and containers on a scheduled basis.
External bruising to potato tubers can result in a blue-black discoloration in the tuber flesh called potato blackspot (PBS). Three potato cultivars used in the Minnesota chipping industry (Atlantic, Frito Lay 1533, and Norchip) were tested for their susceptibility to PBS and compared to Russet Burbank. Tubers were bruised on the stem end using a spring-loaded bruiser and stored at 10°C from 1 to 3 days. PBS was evaluated 24, 48, and 72 hours after bruising. Percentage of bruised tubers showing PBS and Hunter L values of the bruised flesh were used to assess susceptibility. Percentage data showed that the order of most to least susceptible to PBS was Atlantic > Russet Burbank ≥ Frito Lay 1533 > Norchip. L values were not indicative of percentage of tubers showing PBS and may not be accurate measurements of susceptibility to PBS. Atlantic and Russet Burbank tubers were also bruised and stored at 25°C to determine whether a higher storage temperature affected PBS development Atlantic tubers stored at 25°C showed less PBS than those stored at 10°C at each evaluation time. Russet Burbank tubers stored at 25°C exhibited less PBS than those at 10°C at 48 and 72 hr after bruising but not at 24 hr.
Abstract
Respiration, ethylene production, firmness, polygalacturonase activity, cell wall composition, and soluble uronide content were measured during ripening of two tomato (Lycopersicon esculentum Mill.) genotypes, ‘Manapal’ and dark green (dg). Respiration rates and cell wall uronide contents of the two genotypes were similar. Climacteric ethylene production rates of dg fruit were about half that of ‘Manapal’ fruit. Firmness and polygalacturonase activity of dg tomatoes were similar to that of ‘Manapal’ fruit until 55 days postpollination, when dg fruit were twice as firm as ‘Manapal’ fruit and exhibited greater polygalacturonase activity. Soluble uronide content did not differ between the two genotypes, except at 50 days postpollination, when that of dg fruit was 60% that of ‘Manapal’ fruit. Cell wall uronide content of dg fruit was 1.5 times greater than ‘Manapal’ fruit at 55 days postpollination. Although dg fruit contained larger, absolute amounts of cell wall noncellulosic neutral sugars than ‘Manapal’ fruit, net changes in sugar composition were similar throughout ripening. Also, ratios of cell wall arabinosyl or galactosyl residues to cell wall galacturonic acid were similar in both genotypes. These data suggest that firmness differences between dg and ‘Manapal’ fruit are not due to differing activities of polygalacturonase or changes in cell wall composition during ripening, but to other factors that may affect solubilization of cell wall uronides.
During storage, many apple (Malus ×domestica Borkh.) genotypes lose their desirable textural qualities, but some like `Honeycrisp', maintain their sensory Crispness and Firmness. To understand this differential response of genotypes to postharvest changes in texture, reliable and quantifiable methods of texture measurement are needed. This study integrated data from a snapping test, confocal laser scanning microscopy (CLSM), and sensory panels to study postharvest textural changes and to predict sensory textural attributes of Firmness, Crispness, Mealiness, and Juiciness. Three separate analyses on fresh, stored, and combined fresh and stored fruit data yielded different predictors for the same sensory attributes. Change in Crispness during storage was successfully predicted by change in Work during storage. Cell number and size were related to fresh fruit texture and its maintenance during storage. Unique textural properties of `Honeycrisp' were found to be inherited by its progeny.
Narrow-sense heritability and among-family and within-family variance components were estimated for antioxidant activity (AA), total phenolic content (TPH), and anthocyanin content (ACY) in blueberry (Vaccinium L. sp.) fruit. AA, TPH, and ACY were determined in the parents and in 10 offspring from each of 20 random crosses for each of 2 years at Becker, Minn. Offspring-midparent regression analysis provided combined-year heritability estimates of 0.43 ± 0.09 (P ≤ 0.0001) for AA, 0.46 ± 0.11 (P ≤ 0.0001) for TPH, and 0.56 ± 0.10 (P ≤ 0.0001) for ACY. Analyses of variance delineated variation among and within families for AA, TPH, and ACY (P ≤ 0.001). Year-to-year variation in the means for all offspring genotypes was not significant for AA or TPH, but there were changes in rank between years for families and for offspring within families for these traits. Year-to-year variation in the mean for all offspring genotypes was significant for ACY, but rank changes were observed only among offspring within families, not among families. In total, 18 of 200 offspring from 7 of the 20 crosses were transgressive segregants for AA, exceeding the higher parent of the cross by at least two sds. Estimates of variance components showed that variation among families accounted for 24% to 27% of total variance for the three traits. However, variation within families was greater than that among families, accounting for 38% to 56% of total variance for the three traits. These results suggest that increasing antioxidant activity in blueberry through breeding is feasible, and that the breeding strategies utilized should exploit the large within-family variation that exists.