Identification of key sensory and chemical factors determining flavor quality of Xinyu mandarin during ripening and storage

Xinyu mandarin is popular for its good flavor, but its flavor deteriorates during postharvest storage. To better understand the underlying basis of this change, the dynamics of the sensory profiles were investigated throughout fruit ripening and storage. Sweetness and sourness, determined especially by sucrose and citric acid content, were identified as the key sensory factors in flavor establishment during ripening, but not in flavor deterioration during storage. Postharvest flavor deterioration is mainly attributed to the reduction of retronasal aroma and the development of off-flavor. Furthermore, sugars, acids and volatile compounds were analyzed. Among the 101 detected volatile compounds, 10 changed significantly during the ripening process. The concentrations of 15 volatile components decreased during late postharvest storage, among which α-pinene and d-limonene were likely to play key roles in the reduction of aroma. Three volatile compounds were found to increase during storage, associated with off-flavor development.

Effect of pulp cell wall polysaccharides on citrus fruit with different mastication traits

Mastication trait is a primary quality attribute of citrus fruit, influencing consumer demands and industrial processing conditions. However, the underlying causes of differences in mastication traits of citrus remain unclear. In this study, microscopy, spectroscopy and diffraction techniques were applied to investigate the physicochemical properties of Hongmeiren (HMR), Satsuma (WM) and Nanfeng tangerine (NF) with superior, moderate and inferior mastication traits, respectively. Ultrastructure indicated that NF had more neatly arranged and regularly shaped cells than HMR and WM. The monosaccharide composition of NF revealed that multi-branched Na2CO3-soluble pectin (NSF) enhanced intercellular adhesion. Additionally, FT-IR analysis revealed more intense vibrations of O2-H····O6 intramolecular hydrogen bonds within NF cellulose, which resulted in a higher crystallinity of cellulose (73.75%) than HMR (32.53%) and WM (43.76%). Overall, the high content and crystallinity of cellulose, the multi-branched NSF and the high content of hemicellulose contributed to the inferior mastication trait of citrus fruit.

Comprehensive Evaluation of Raw Eating Quality in 81 Sweet Potato (Ipomoea batatas (L.) Lam) Varieties

The raw eating quality of sweet potato is complex. As consumers start paying more attention to the raw eating quality of tuberous roots in sweet potato, the evaluation of the raw eating quality of sweet potato is becoming an important issue. Therefore, we measured 16 quality indicators in 81 varieties of sweet potato. It was found that these 16 quality traits had different coefficients of variation (C.V.). Among them, the C.V. of fructose, glucose, and adhesiveness were the largest: 87.95%, 87.43% and 55.09%, respectively. The cluster analysis method was used to define six categories of the different tuberous roots of sweet potato. Group I, III, and IV had a stronger hardness and higher starch and cellulose content. Groups II, V, and VI were softer, with a high moisture and soluble sugar content. The principal component analysis method was used to comprehensively evaluate 16 quality indicators of 81 sweet potato varieties. It was found that Futian1, Taishu14, and Nanshu022 are good varieties in terms of raw eating quality. These varieties have low hardness, high adhesiveness in texture, high soluble sugar content, and low starch and cellulose. Future research should focus on improving the raw eating quality of sweet potato by reducing hardness, starch, and cellulose, while increasing adhesiveness, soluble sugar, and moisture content.

Effects of packinghouse operations on the flavor of 'Orri' mandarins

Mandarins have a delicate flavor and are easy to peel and easy to consume. However, they are relatively perishable and suffer from flavor deterioration after harvest. The goal of the current study was to examine the effects of commercial packinghouse operations on the flavor of 'Orri' mandarins. For that purpose, we collected fruit from four different points along a commercial citrus packing line: (1) directly from the harvest bin, (2) after application of a hot (53°C) fungicide treatment for 30 s, (3) after waxing, and (4) after waxing and after the fruit had passed through a hot-air drying tunnel (37°C) for 2 min. The collected fruit were stored for 3 or 6 weeks at 5°C and then kept for five more days under shelf-life conditions at 22°C. The observed results indicate that the hot fungicide treatment had no effect on flavor quality. However, the waxing and waxing +drying treatments resulted in significant increases in ethanol accumulation, lower flavor-acceptability scores, and increased off-flavors. Gas-chromatography mass-spectrometry (GC-MS) analysis revealed that the waxing and waxing +drying treatments resulted in particular increases in the levels of alcohol and ethyl ester volatiles; whereas levels of other aroma volatiles (i.e., esters, aldehydes, monoterpenes, and sesquiterpenes) decreased after storage in all fruit samples. Overall, the waxing process in commercial citrus packinghouses increased ethanol and ethyl ester volatile levels and harmed flavor acceptability. These findings demonstrate the need to identify new wax formulations that do not hamper fruit-flavor quality.

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.

Effect of information about mandarin internal maturity on consumer hedonic and sensory expectations: a cross-cultural study in Spain and Mexico

BACKGROUND

Under certain climate conditions, citrus fruit may reach optimum internal maturity while the rind is still green. It is therefore customary to enhance skin colour changes by submitting early citrus varieties to ethylene degreening treatment, which implies a cost and may result in external disorders. In this study, the effect on consumer expectations (sensory and hedonic) of providing them with information about the internal maturity of non-degreened mandarins (greenish-coloured rind) was evaluated.

RESULTS

Mandarins with three different external colour indices (CI), CI = -6, CI = +1 and CI = +5, and three ways of conveying information, were investigated: (i) No information (NoInfo), (ii) The text 'Mandarins ready to eat' (Text) and (iii) Text + Visualisation of mandarin flesh (orange-coloured in all cases) (Text+Flesh). Consumer expected liking, purchase intention and sensory expectations were markedly affected after receiving the different information types. The greatest effect was detected when Text+Flesh information was provided. Rind mandarin colour was also a determinant factor of how consumer expectations were modified by the received information. Moreover, our results revealed some differences among Spanish and Mexican consumers, since maturity information had a stronger effect on hedonic expectations of Mexican consumers.

CONCLUSIONS

When mandarins reach CI = +5 (pale orange-coloured rind with small areas still green), letting consumers know that mandarins are ready to eat by means of Text+Flesh information may be a non-cost strategy to avoid degreening treatment or to shorten its length. © 2021 Society of Chemical Industry.

Consumer Information Needs and Sensory Label Design for Fresh Fruit Packaging. An Exploratory Study in Spain

In recent decades, packaged fruit has gained market ground over loose fruit, and fruit containers have become a source of information for consumers. This study approaches three objectives related to consumer information needs for decision making when purchasing fruit: (1) Determine if consumers' choice of packaged fruit rather than loose fruit is motivated by their interest in the information provided on packaging; (2) identify information gaps on fruit packaging labels; (3) identify those sensory attributes that consumers consider to be of major interest to be included in sensory labels of different fruit types. The study was based on an online questionnaire answered by 394 fruit consumers. Ninety percent of the participants stated having an interest in receiving information when purchasing fruit, but their choice between packaged or loose fruit was not conditioned by their information needs. Moreover, a gap between information interest and information use was detected as their final purchase decisions were not always based on the provided information. 'Harvest date', 'production method', 'percentage of the price received by the farmer', 'applied treatments', 'sensory characteristics', and 'environmental information' were identified as the major information gaps, as these labels were unavailable for a high percentage of consumers, who stated their interest in them. According to consumers, sensory labels should include information about 'sweetness' and 'flavor intensity' irrespectively of fruit type. 'Sourness' and 'juiciness' attributes were particularly interesting for citrus, as 'sourness' and 'firmness' were for kiwi. Information about texture properties was required for pome and stone fruit. Other attributes, such as easiness to peel, were important only for citrus fruit.

Investigating sensory properties of seven watermelon varieties and factors impacting refreshing perception using quantitative descriptive analysis

Watermelon (Citrullus lanatus) is known for its refreshing quality, though its sensory attributes have never been related to its perceived refreshment. Modified quantitative descriptive analysis by a trained panel was used to examine the sensory profile of seven watermelon varieties. Eleven attributes including perceived refreshing intensity were measured on a 0-10 line scale using chemical references. Watermelon samples were evaluated with and without nose clips to control orthonasal and retronasal aroma and temperature was included as a variable to observe their effects on perceived refreshment. The dominant watermelon attributes were wateriness, refreshing, crispness, sweet, mealiness, fresh, ripe, and melon. The varieties were best differentiated by refreshing (p < 0.001), crispness (p = 0.002), sweet (p < 0.001), mealiness (p = 0.016), green (p = 0.007), and sour perception (p < 0.001). Captivation and Excursion were the most refreshing varieties. Captivation, Excursion, and Seedless varieties were less refreshing when flavor perception was inhibited; ratings ranged from 6.8 to 7.2 without nose clips and 5.9-6.0 with nose clips (p = 0.002). Refreshing was most positively driven by wateriness, followed by crispness, fresh, melon, and sweet, and negatively driven by mealiness, as indicated by partial least square regression. Samples served cold were more refreshing (ratings of 7.1 without and 6.0 with nose clips) than those served at room temperature (ratings of 4.9 without and 3.5 with nose clips), p < 0.001. This study defined the sensory profile of seven watermelon varieties and showed that flavor, texture, and temperature were responsible for the refreshing perception of watermelon for the first time.

Consumer Description by Check-All-That-Apply Questions (CATA) of the Sensory Profiles of Commercial and New Mandarins. Identification of Preference Patterns and Drivers of Liking

In the last few years, the interest in developing new mandarin cultivars of superior quality has grown as a response to the increasing consumer demand of this appreciated fruit. This study evaluated the sensory profiles of five new late-season mandarin cultivars (‘Alborea‘, ’Coral‘, ’Omet‘, ’Matiz‘ and ’Tri-703‘) and six commercial cultivars found contemporarily in stores (‘Clemenules‘, ’Nova‘, ’Tango‘, ’Nadorcott‘, ‘Orri’ and ‘Ortanique’). The sensory profiles of the cultivars were described by consumers through CATA questions. Consumers’ acceptability and the main physico-chemical properties were also evaluated. Twenty-two out of 23 CATA terms differed significantly for the sensory profiles of the studied cultivars. The new cultivars shared a similar profile, described mainly as “very intense taste”, “refreshing taste”, “very aromatic” and “juicy”, and these characteristics were quite different from those of the commercial cultivars. By combining acceptability and CATA questions, drivers of liking for segments of consumers with different preference patterns were identified. This is the first time that the sensory profiles of mandarin cultivars have been described by consumers. A significant number of consumers preferred the new mandarin cultivars to the commercial ones, which allows them a promising introduction on the market.

Mandarin fruit quality: a review

During the last decade, there has been a continuous rise in consumption and global marketing of fresh, easy-to-peel mandarins, with current annual production of nearly 29 million tons. Nevertheless, most of the existing knowledge on quality traits of citrus fruit comes from research conducted on oranges and grapefruit, which are the main products for the citrus juice manufacturing industry; relatively little is yet known regarding the unique fruit quality traits of mandarins, nor about the great diversity in these traits among the various natural sub-groups and varieties of mandarins. In the present review we discuss the physiological, biochemical, and molecular factors governing key fruit quality attributes of mandarins, including fruit colour, size and shape, ease of peeling, seedlessness, flavour, and nutritional quality. Fruit colour, size, and shape contribute to external appearance; peelability and seedlessness to ease of consumption; and flavour and nutritional quality to internal quality. © 2017 Society of Chemical Industry.

Characterizing and improving the sensory and hedonic responses to polyphenol-rich aronia berry juice

Interest in nutrient-rich berry juices is growing, but their high polyphenol levels render them sensorily unappealing. Fifty adults, who were assessed for sensory phenotype and dietary behaviors, provided sensory and palatability ratings of juices from 'Viking' aronia berries for each of seven harvest weeks. By peak harvest, juice preference increased two-fold, averaging neither like/dislike. This hedonic shift was associated with: increases in juice sugars paralleling increases in perceived sweetness (maximum = weak); reductions in percent acidity paralleling reductions in sourness (minimum = moderate), astringency (minimum = to just above weak) and bitterness (minimum = just below weak). About 25% of adults liked the aronia juice, including adults who also liked an aqueous citric acid solution (average rating = moderately sour) or those who reported adventurous eating behaviors. Bitter taste phenotype, measured by propylthiouracil or quinine bitterness, failed to explain significant variation in juice sensation or preference. We also collected sensory and preference ratings from juice collected at peak harvest blended with sugar and/or sweet olfactory flavoring (10 ppm ethyl butyrate). Increasing juice sweetness by adding 5% sucrose decreased sourness and improved preference from weak dislike to weak like. Adding sweet olfactory flavoring decreased juice sourness without changing preference. Adding sweet flavoring and 3% sucrose resulted in reduction of sourness and improvements in preference ratings comparable to 5% added sucrose. Neither added sugar nor flavoring blocked juice astringency. In summary, these findings suggest that aronia juice, even from berries picked at peak harvest, appealed to only a few adults (sour likers or adventurous eaters). Although enhanced sweetness, with added sugar and sweet olfactory flavoring, improved aronia juice preference, broader sensory approaches are required to blunt astringency for greater consumer appeal.

Diversity among mandarin varieties and natural sub-groups in aroma volatiles compositions

BACKGROUND

Mandarins constitute a large, diverse and important group within the Citrus family. Here, we analysed the aroma volatiles compositions of 13 mandarin varieties belonging to seven genetically different natural sub-groups that included common mandarin (C. reticulata Blanco), clementine (C. clementina Hort. ex. Tan), satsuma (C. unshiu Marcovitch), Mediterranean mandarin (C. deliciosa Tenore), King mandarin (C. nobilis Loureiro), and mandarin hybrids, such as tangor (C. reticulata × C. sinensis) and tangelo (C. reticulata × C. paradisi).

RESULTS

We found that mandarin varieties among tangors ('Temple', 'Ortanique'), tangelos ('Orlando', 'Minneola') and King ('King') had more volatiles, at higher levels, and were richer in sesquiterpene and ester volatiles, than other varieties belonging to the sub-groups common mandarin ('Ora', 'Ponkan'), clementine ('Oroval', 'Caffin'), satsuma ('Okitsu', 'Owari') and Mediterranean mandarin ('Avana', 'Yusuf Efendi'). Hierarchical clustering and principal component analysis accurately differentiated between mandarin varieties and natural sub-groups according to their aroma-volatile profiles.

CONCLUSIONS

Although we found wide differences in aroma-volatiles compositions among varieties belonging to different natural sub-groups, we detected only minor differences among varieties within any natural sub-group. These findings suggest that selecting appropriate parents would enable manipulation of aroma-volatile compositions in future mandarin breeding programmes.