Gayle M. Crisosto

Consumer acceptance of 'Brooks' and 'Bing' cherries is mainly dependent on fruit SSC and visual skin color

During two seasons, ‘in-store’ consumer acceptance tests were performed to determine the relationship between soluble solids concentration (SSC), titratable acidity (TA) and visual skin color on ‘Brooks’ and ‘Bing’ cherry consumer acceptance. For this, approximately 600 consumers were presented cherry samples at targeted skin colors with SSC in the range of ca. 13.0 � /20.0% and TA in the range of ca. 0.50 � /1.00%. For each cherry sample, one half of the whole cherry was tasted and the other half was used to determine SSC and TA. TA � /0.60% reduced consumer acceptance on ‘Brooks’ cherries with B/16.0% SSC compared to cherries with 5/0.60% TA, while in ‘Bing’ the same situation only occurred on cherries with 5/13.0% SSC. High consumer acceptance was determined on ‘Brooks’ and ‘Bing’ cherries when SSC were � /16.0% without regard to TA. For both cultivars, the highest percentage of American consumers would buy cherries based on dark skin color without regard to ethnic group (Caucasian, Asian American, Hispanic, or Black) or gender. However, consumer age was related to making the ‘buy’ or ‘not to buy’ decision based on cherry skin color. Consumers under 18 years old were less biased to buy cherries based on visual skin color. Thus, this work demonstrated that for ‘Brooks’ and ‘Bing’ cherries, a full bright red or dark mahogany skin color should be reached, respectively, in addition to a minimum SSC of 16.0% to satisfy the majority of American consumers. # 2002 Elsevier Science B.V. All rights reserved.

Carbon dioxide-enriched atmospheres during cold storage limit losses from Botrytis but accelerate rachis browning of 'Redglobe' table grapes

We evaluated a range of CO2 and O2 concentrations as a potential substitute to SO2 treatments for controlling decay development on ‘Redglobe’ table grape during storage. During the 1998 season, early (14% soluble solids concentration, SSC) and late harvested (17% SSC) ‘Redglobe’ grapes were stored in 16 controlled atmospheres of 5, 10, 15, 20, and 25 kPa CO2 combined with 3, 6, and 12 kPa O2. During the 1999 season, 10 or 15 kPa CO2 combined with 3, 6, and 12 kPa O2 were tested in comparison with air stored grapes as control. In the 2000 season, late harvested ‘Redglobe’ grapes were kept in 12 kPa CO2+ 6k Pa O 2 in comparison with standard commercial storage practices of SO2 fumigation. None of the atmospheres tested for up to 12 weeks at 0 °C influenced SSC, titratable acidity (TA), SSC:TA, or berry shatter and browning. Rachis browning was accelerated and trained judges perceived ‘off-flavor’ in grapes exposed to CO2 levels above 10 and 15 kPa for early and late harvested ‘Redglobe’ grapes, respectively. Atmospheres including above 10 kPa CO2 controlled decay incidence and spread among berries (nesting) independent of O2 concentrations during storage at 1 °C for up to 8 weeks and after 3 days at 20 °C, simulating a retail display period. Based on these data, a combination of 10 kPa CO2 with 3, 6 or 12 kPa O2 is suggested for up to 12 weeks storage for late harvested ‘Redglobe’ grapes. An atmosphere of 10 kPa CO2+ 6k Pa O 2 is suggested for early harvested ‘Redglobe’ grapes, but not to exceed 4 weeks.

Understanding consumer acceptance of early harvested 'Hayward' kiwifruit

During two seasons, ‘in-store’ consumer acceptance tests were performed to determine the relationship between ripe soluble solids concentration (RSSC) and/or ripe titratable acidity (RTA) on ‘Hayward’ kiwifruit consumer acceptance. For this, 252 consumers were presented kiwifruit slice samples with RSSC of 11.0, 12.0, 13.0, and 14.0% with a RTA ranging from 0.8 to 1.2%. Kiwifruit with RSSC that ranged from 11.6 to 13.5% were always liked by consumers but with different degrees of liking. A 12.5% RSSC is proposed as a minimum quality index for early-marketed kiwifruit. RTA played a significant role in consumer acceptance only on kiwifruit that had RSSC11.6% with RTA1.17% (‘sour’). This kiwifruit quality survey indicated that some vineyards had kiwifruit with RSSC higher than 12.5% before they met the recommended minimum maturity standard of 6.5% HSSC. Kiwifruit picked with SSC6.2% developed flesh breakdown. This work demonstrated that some California vineyards could produce high taste quality (12.5% RSSC) kiwifruit before they reach 6.5% SSC measured when kiwifruit are hanging on the vines.

Understanding American and Chinese consumer acceptance of 'Redglobe' table grapes

‘In-store’ consumer acceptance tests were performed on a group of 400 American consumers and 250 native Chinese consumers to determine the relationship between ripe soluble solids concentration (SSC) and titratable acidity (TA) on consumer acceptance of ‘Redglobe’ grapes for different ethnic groups. For this, a group of Caucasian, Hispanic and Chinese-American consumers and a group of native Chinese consumers tasted monadically four individual berry half samples at room temperature with SSC ranging from 10 to 20% and TA from 0.30 to 1.80%. Grapes with SSC 16.1% were accepted by 70% of the American consumers and 47% of the Chinese consumers. However, the percentage of consumers that disliked these grapes was the same ( 21) for both ethnic groups. The difference in the percentages of Chinese and American consumers accepting the grapes was due to the ‘neither like nor dislike’ category. Chinese consumers chose the ‘neither like nor dislike’ category in approximately 34% of the cases, while approximately only 7% of the American consumers chose it. Our data confirmed that ‘Redglobe’ consumer acceptance is highly related to SSC:TA ratio but within a given SSC and TA level. In contrast to American consumers, Chinese consumer acceptance was not related to SSC:TA ratio when TA 0.80%. Thus, our work indicates that high TA affects consumer acceptance in relation to SSC:TA ratio depending on ethnic background.

Testing the reliability of skin color as an indicator of quality for early season 'Brooks' (Prunus avium L.) cherry

During the 1997–1999 seasons, we investigated the relationship between ‘Brooks’ cherry skin color at harvest (full light red, 50% bright red, full bright red and full dark red) and consumer acceptance using fruit grown in different geographic locations in the San Joaquin Valley (SJV). Soluble solids concentration (SSC) increased, but titratable acidity (TA) levels did not decrease as cherries matured from the full light red to full dark red skin color. The perception of sweetness, sourness and cherry flavor intensity by a trained taste panel was highly correlated to skin color, SSC and SSC:TA at harvest. There were no differences in the level of correlation between SSC or SSC:TA and the perception of sweetness, sourness or cherry flavor by trained judges. In-store consumer tests indicated that ‘Brooks’ cherries with SSC16.1% had the highest consumer acceptance (ca. 80–90%) and cherries with SSC 16.0%, the lowest (ca. 48%). Gender and ethnicity (Caucasian, Asian American, Hispanic, or African American) did not affect American consumer acceptance of ‘Brooks’ cherries.

EVALUATION OF A NON-DESTRUCTIVE DRY MATTER SENSOR FOR KIWIFRUIT

In this work we studied the relationship between kiwifruit dry matter (DW) measured using the destructive method with a fruit dehydrator (Nesco/American Harvest®, Wisconsin, USA) and a non-destructive Kiwi meter sensor (Turoni Inc., Forli, Italy). This was an approach to develop a reliable non-destructive method to predict harvest and postharvest quality based on dry matter. There was a significant, but low correlation between DM determined non-destructively using the Kiwi meter and destructively using the fruit dehydrator (industry standard). Classification models with discriminant analysis were used to segregate kiwifruit into groups according to DM. Using this statistical approach rather than the relationship between the two methods, kiwifruit were consistently segregated into two DM groups, but classification into three groups yielded lower scores. These results indicate that the Kiwi meter is a reliable and fast sensor to segregate kiwifruit according to their DM content that could be considered as a consumer quality at harvest and/or postharvest index. Further work on the optimization of this non-destructive sensor as a tool to define consumer kiwifruit quality is being carried out by our group. INTRODUCTION Currently, kiwifruit is marketed worldwide. This globalization has created economic advantages for early and late harvest kiwifruit sales, when commodity availability is low and prices are high. This situation has created an incentive for early harvest, which can result in low consumer-quality kiwifruit in the market, reducing repeat purchases of kiwifruit and overall demand (Woodward and Clearwater, 2008). Therefore, a more reliable, fast, and simple quality index that assures taste quality, protecting consumers, is needed. Because dry matter (DM) includes starch concentration, and is highly correlated with ripe SSC and final soluble sugars after ripening (Harker et al., 2009; Hopkirk et al., 1986; Jordan et al., 2000), researchers from various countries have proposed the use of DM concentration as a quality index. As a result, some industries have started its use for trading. Non-destructive sensor methods, such as near infrared spectroscopic (NIR) analysis or density, can be used to assess kiwifruits in terms of their dry matter content and/or ripened soluble solids content (SSC) (Crisosto et al., 2009; McGlone et al., 2002; Moghimi et al., 2010; Nicolai et al., 2007). The commercial motivation underlying these methods is the desire for fast grading, according to optimum, consumer-defined quality. The taste of ripe ready-to-eat kiwifruit is largely determined by the fruit SSC, and this final SSC is highly correlated with the DM of unripe fruit. The research objective of this study was to assess the accuracy of the Kiwi meter non-destructive sensor to determine kiwifruit quality, compared with destructive, traditional methods. The main goal of this study is the non-destructive prediction of the DM of kiwifruit, in order to provide a fast and non-destructive parameter to decide the correct time of harvest based on consumer acceptance. MATERIALS AND METHODS For this study, kiwifruits (‘Hayward’) were evaluated for destructive and nondestructive dry matter content. Fruit was harvested from experimental and commercial fields in California and Chile at its commercial maturity. Fruit was transported to UC