Physicochemical and sensorial evaluation of new varieties of acerola

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Physicochemical and sensorial evaluation of new varieties of acerola
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  Physico-chemical and sensorialevaluation of new varieties ofacerola M.E.O. Mamede and M.P.S. Miranda  Federal University of Bahia, Bahia, Brazil  R. Ritzinger and R.C.B. Godoy  Embrapa Cassava and Tropical Fruits, Cruz das Almas, Bahia, Brazil, and  E.S. Velozo  Federal University of Bahia, Bahia, Brazil  Abstract Purpose  – Thepurpose ofthispaper istoevaluate thechemical, physical andsensorycomposition of three new varieties of acerola (Rubra, Cabocla and CMF 017). Design/methodology/approach  – The samples of ripe acerola were collected from the ActiveGermoplasm Bank of Embrapa Cassava and Tropical Fruits – Cruz das Almas/Bahia, from thespecies  Malpighia emarginata  DC and analyzed by using standard methods. Findings  – The findings were that the Rubra variety stood out among the others in terms of flavourand purchasing intention, probably due to its pH 3.60, total acid (0.83 percent malic acid) and VitaminC (911.97g ascorbic acid/100g) which gave the variety a less acidic flavour. As regards size, theaverage acceptability of this variety was 6.01, statistically different from Cabocla (8.08). Totalanthocyanins were also found to be the highest, 76.7mg/100g and therefore the antioxidant activity of the peel was greater (85 percent) compared with the other varieties, though not differing statisticallyfrom the CMF 017 variety. According to these results, the Rubra variety is the one which should be of most interest to producers. Practical implications  – The new variety often fails to exceed nutritional and organolepticcharacteristics of existing varieties in the market with established acceptance levels. The paper evaluatesthechemicalandsensorialcompositionofnewvarietiesofacerolafruit,whichcouldbelaunchedontothemarket. It was observed that one particular variety had better sensorial and nutritive quality. Originality/value  – This kind of data is important both for consumers who want to buy the bestquality fruit and producers who want to plant more of the better quality variety so that they can gaingreater added-value in the commercialization of the fruit. Keywords  Brazil, Fruits, Vitamins Paper type  Research paper Introduction Acerola, also known as the Antilles cherry, belongs to the Malpighiaceae family genusMalpighia. The most commonly cultivated acerola in Brazil is the species  Malpighiaemarginata  DC (Oliveira  et al.  2003). Depending on the variety, it can be round, oval oreven conical in shape and the pigmentation of its skin can vary from orange to purpleaccording to the presence of anthocyanins (Carvalho and Manica, 1993). The current issue and full text archive of this journal is available at www.emeraldinsight.com/0007-070X.htm The authors would like to thank Embrapa Cassava and Tropical Fruits, Cruz das Almas, Bahia,Brazil for donating the fruit samples. Physico-chemicaland sensorialevaluation 387 British Food JournalVol. 111 No. 4, 2009pp. 387-395 q Emerald Group Publishing Limited0007-070XDOI 10.1108/00070700910951867  Some authors have found anthocyanin values of between 3.79mg/100 and59.74mg/100g in the skin depending on the variety of acerola (Lima  et al. , 2003).Malvidin, pelargonidin and cyanidin have been mentioned as the principal anthocyaninspresent in acerola (Silva  et al. , 1998). Anthocyanins not only provide the colour forflowers, fruits and roots but they are also powerful antioxidants (Francis, 1989). Theantioxidant activity of these compounds is linked to their chemical structure, or moreprecisely to groups of hydroxyl present in the rings A and B (Rice-Evans  et al. , 1996).Furthermore, acerola stands out among other fruits for having a particularly highvitamin C content, which can vary between 1,000 and 1,677.5mg/100g (Philippi, 2001).These amounts are considerable when compared to oranges, which have 54mg/100g(Tabela Brasileira de Composic¸a˜o de Alimentos (TACO), 2004). Vitamin C is alsoconsidered to be a powerful antioxidant with free radicals. Antioxidants can inhibit orslow down oxidative reactions and are therefore important compounds in theprevention of certain types of cardiovascular diseases, cancer, inflammations,Parkinson and Alzheimer’s diseases (Halliwell, 2000; Aruoma, 1998).Nowadays Brazil is the largest producer, consumer and exporter of acerola (Cecı´lio et al. , 2004). The biggest producers of acerola at state level are: Pernambuco whichproduces 23.11 percent, followed by Ceara´ with 14.32 percent, Sao Paulo with 11.39percent and Bahia with 10.48 percent. The Northeast region of the country isresponsible for 69.6 percent of production. Both the soil conditions and the climate of the Northeast lend themselves to the production of an excellent quality fruit all yearround, suitable for supply to the European, Asian and American market at any timeof the year. This has led to the setting up of large agro-industrial undertakingsbringing jobs to the poor semi-arid regions of the country. Some of the pre-requisitesfor export to Europe and Japan include a total solid soluble content of equal to orgreater than 7.0 8 Brix, vitamin C content of over 1,000mg ascorbic acid/100g of pulp(Alves, 1996).New varieties of acerola have emerged in the search for greater resistance to diseaseand pests and mechanical damage, to enhance colour, size and to alter the compositionof its chemical components, etc. Genetic improvements mainly aim to modify thenegative characteristics of the product but inevitably end up modifying the positivecharacteristics such as the components responsible for taste and aroma. Sensoryanalysis is being increasingly used to evaluate the quality of new varieties of fruits “innatura” (Matsuura  et al. , 2002; Santana  et al. , 2004(. This is because the sensoryqualities are as important for the consumer as size, disease resistance and price are forthe producer. This work analysed the chemical constituents and the sensorialacceptability of three new varieties of acerola collect in the month of November. Thepreliminary results of the sensorial acceptability, chemical and physical data of fruitcollected one occasion (November) are presented. Material and methods  Materials The samples of ripe acerola (three varieties: CMF 017, RUBRA, CABOCLA) werecollected from the Active Germoplasm Bank of Embrapa Cassava and Tropical Fruits – Cruz das Almas/Bahia, from the species  Malpighia emarginata  DC. The fruit(approximately 3kg) was collected without stems, washed and dried. Immediatelythereafter, sensorial, chemical and physical analyses were carried out and then after 48 BFJ111,4 388  hours in a freezer at  2 20 8 C the antioxidant activity, total anthocyanins and flavonolsanalyses. Ten fruits of each variety were weighed and diameter of the fruit wasmeasured using a micrometer. Methods  Physico-chemical analysis From the whole fruit, a pulp was made. The following parameters were measuredusing this pulp: .  Measurement of pH   – The pH of the pulp was determined by using digital pHmeter. . Total soluble solids  – TSS were determined by using refractometer and theresults expressed as  8 Brix, Method 932.14C (AOAC, 1990). . Titratable acidity  – was carried out using AOAC method no. 942.15, 1990, andresults expressed in malic acid percent. . Vitamin C   – by titrimetry with 2,6 Diclorophenol indolphenol, Tillman method(Lees, 1975).This analysis was done in triplicate and data were analyzed by analysis of variance(ANOVA) and Tukey test, employing SAS Software (1997). Sensory analysis The acceptability tests for the attributes aroma, flavour, colour, succulence and sizewere carried out by 50 consumers who said they liked acerola. The analyses werecarried out in booths and with lighting. All the samples were codified with digitnumbers. A 9cm non-structured hedonic scale was used for each attribute and thepurchasing intention was recorded on a five-point attitude scale on the same scoresheet (Meilgaard  et al. , 1983; Stone and Sidel, 1993). Statistical analysis was carriedout using Analysis of Variance (ANOVA) and Tukey test, employing SAS Software(1997).  Extraction and measurement of total anthocyanins and flavonols The extraction and measurement of total anthocyanins and flavonols in the skin of 400g of acerola were carried out according to Lee and Francis (1972) in triplicate.Absorbance readings were done at 535 and 374nm to quantify the total anthocyaninsand flavonols respectively. The absorbance coefficient used was 98.2 for anthocyaninsand 76.6 for flavonols (Lee and Francis, 1971). The data were analyzed by ANOVA andTukey test, employing SAS Software (1997).  Analysis of anthocyanidins The extract of anthocyanins was heated to 60 8 C in a vacuum to obtain theanthocyanidins in triplicate. The separation of the pigments was carried out inchromatographic paper used WHATMAN no. 3 paper. O The mobile phase was BAW(butanol, acetic acid and water in proportion 4:1:5 (v/v). The identification was done bycomparing the retention times, and, also specific reactions with the AlCl 3  (Harbone,1973). The data were analyzed by average and standard deviation. Physico-chemicaland sensorialevaluation 389   Antioxidant activity –   b  -carotene-linoleic acid assay In this work the anti-oxidative capacity of the composition of the skin for the acerolawere determined by the inhibition of conjugated diene hydroperoxides arising fromlinoleic acid oxidation. A solution of  b  -carotene-linoleic acid was prepared according toDapkevicius  et al.  (1998) in triplicate. Quantities of 200 m L of an extract of anthocyanins, obtained of the skin of 400g of acerola, were incubated with 5ml of the b  -carotene-linoleic acid emulsion for 120 minutes at room temperature. After thisincubation period, absorbances of the mixtures were measured at 470nm. The sameprocedure was repeated with the synthetic anti-oxidant, butylated hydroxytoluene(BHT) as positive control, and a blank. The anti-oxidative capacities of the extractswere compared with those of BHT and blank. The results were expressed inpercentages of anti-oxidative capacity. The data were analyzed by ANOVA and Tukeytest, employing SAS Software (1997). Results and discussion  Physico-chemical composition Acerola is an acidic fruit with a pH of between 3.11 and 3.41 (Musser, 2001). The pH forthe variety CMF 017 was 3.29 and for the Rubra variety 3.60. These results show thatthe new varieties have a pH above the minimum (3.11) and the maximum (3.41) foundby Musser (2001). Total acidity also reflects the pH, as the higher the pH, the lower thetotal acidity (Table I). The Rubra variety has a higher pH and therefore a lower acidcontent (0.83g/100g malic acid).The Rubra variety stood out in terms of Total Soluble Solids (TSS) (8.840 8 Brix),compared to CMF 017 and Cabocla. The variety CMF-017 and Cabocla had lower TSSand there was no significant difference between them. These amounts were differentfrom those reported by Franc¸a (1999) and Musser (2001) in other varieties. Theamounts found for the varieties studied, were all within the limits required, by the Japanese and European market, the biggest importers of the product.The average vitamin C content, expressed in ascorbic acid in the three varieties wasnear or above the levels recommended by the breeding program, in other words higherthan 1,000mg ascorbic acid/100g (Table I). Compared to other fruits, acerola has otheradvantages: the vitamin C content and the number of calories. The guava, for example,has 217.6mg/100g ascorbic acid, but it generates 69/100g, while acerola has levels of  Varieties CMF-017 Cabocla RubrapH 3.29 c 3.46 b 3.60 a SST 8 Brix 7.88 b 8.02 b 8.84 a ATTPercent malic acid 1.36 a 1.11 b 0.83 c SST/ATT 5.84 a 7.27 b 10.72 a Vitamin Cg ascorbic acid/100g 1,191.91 a 1,052.23 ab 911.97  b Diameter (cm) 2.5 a 3.0 b 2.4 a Mass (g) 6.5 a 9.0 b 6.7 a Note : Means within a line followed by same letters do not differ significantly by Tukey test (   p  ,  0 : 05) Table I. Physico-chemical data of the acerola varieties BFJ111,4 390  ascorbic acid, which are at least four times higher (911.9mg/100g ascorbic acid in theRubra variety) and in 100g it produces only 32 calories. Thanks to this, acerola hasbeen described as both a “functional” and “light” fruit. Sensory evaluation and correlations The average acceptability for flavour, between 5.12 and 6.43, which corresponds to“quite liked” and “liked moderately”, revealed that the samples had acceptability abovethe descriptor “neither liked nor disliked”, i.e. the data did not show any doubts inacceptability. The Rubra variety had greater levels of acceptability for flavour (6.43,see Table II) and also the highest purchasing intention for the descriptor “definitelywould buy” (Figure 1). However, this variety had the lowest vitamin C content and thehighest pH value. These chemical characteristics probably give the variety a less acidtaste than the others. The variety CMF 017 had the highest vitamin C content(1191.91mg ascorbic acid/100g of pulp) and the lowest average acceptability of all thevarieties (5.12) for the attribute flavour. The high concentration of vitamin C lowers thepH and makes the fruit particularly acid. The Cabocla variety was between the othertwo varieties in terms of vitamin C content, however, it had the highest averageacceptability for aroma (6.77, see Table II). Mean acceptabilityAttributes CMF 017 Cabocla RubraFlavour 5.12 b 5.56 ab 6.43 a Aroma 4.84 a 6.77 bc 5.46 ca Size 5.11 a 8.08 b 6.01 ac Succulence 5.12 a 5.85 a 5.77 a Colour 6.0 a 6.4 a 5.39 a Note : Means within a line followed by same letters do not differ significantly by Tukey test (   p , 0 : 05) Table II. Mean acceptability of thevarieties of acerola Figure 1. Consumer purchasingintention of varieties of acerola (November 2005) Physico-chemicaland sensorialevaluation 391
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