Fruit Quality Characteristics and Biochemical Composition of Fully Ripe Blackberries Harvested at Different Times.

Maja Mikulic-Petkovsek,Metka Hudina,Mateja Senica,Zala Zorenc,Darinka Koron,Robert Veberic

doi:10.3390/foods10071581

Maja Mikulic-Petkovsek, Metka Hudina + Show 4 more

Open Access

https://doi.org/10.3390/foods10071581

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Abstract

We investigated how the quality of blackberry fruit changes during the ripening period. Since it is difficult to predict picking dates for blackberries, we were interested in how the quality of fully ripe fruit changed depending on the sampling date (from 28 July to 1 September). Blackberries (at full ripeness) were sampled at six weekly intervals and the contents of sugars, vitamin C, organic acids and phenolic components were analysed by high performance liquid chromatography combined with mass spectrometry. The colour parameters, total soluble solids and weight of the fruits were also measured. The results showed that the fruits at the last sampling had a significantly lower fruit weight and higher soluble solids. ‘Cacanska Bestrna’ had the highest fruit weight and vitamin C content (11.43 mg/100 g). The main sugars in blackberries were fructose (13.8–33.4 g/kg FW) and glucose (13.0–33.2 g/kg FW). ‘Loch Ness’ and ‘Navaho’ had a sweeter taste since they had the highest ratio of sugars and acids (S/A approx. 5.8) and ‘Smoothstem’ and ‘Thornfree’ had the sourest taste, with a ratio of S/A 2.5. Blackberries harvested at the first two samplings had lower anthocyanin contents than fruits from later sampling times. There were no significant differences in the content of flavonols, ellagitannins, flavanols or hydroxycinnamic acids during the ripening period. The content of vitamin C in the fruits did not change among samplings, but the fruits had a higher content of organic acids at the first two or three samplings. The results may be useful for both the processing industry and growers to set quality standards for each variety and to determine the optimal harvest time.

Highlights

Blackberries (Rubus fruticosus L.) are grown all over the world, but areas with mild winters and long temperate summers are more suitable for their growth
Throughout the ripening period of blackberries, we sampled the fruits at six weekly intervals and monitored the fruit quality parameters
We performed a chemical analysis of the fruit, by which we determined the content of individual sugars, organic acids, vitamin C and the content of phenolic substances

Summary

Introduction

Blackberries (Rubus fruticosus L.) are grown all over the world, but areas with mild winters and long temperate summers are more suitable for their growth. The main areas of blackberry production are North America, Europe, Asia, South America, Central America and Africa. Many high-quality and high yield varieties are used today in blackberry production [1]. Blackberries are present on the market for the purpose of fresh consumption; more often, they are processed into juices, jams, purees, concentrates and sweets. The quality of the fruit is extremely important for the consumer and the food industry, both the external appearance of the fruit and the internal quality, which is directly related to the content of primary and secondary metabolites. It is important to remember that high-quality fruit has a higher market value [2]

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