Grapefruit (Citrus paradisi Macfad) Phytochemicals Composition Is Modulated by Household Processing Techniques

Abstract

Grapefruits (Citrus paradisi Macfad) contain several phytochemicals known to have health maintaining properties. Due to the consumer's interest in obtaining high levels of these phytochemicals, it is important to understand the changes in their levels by common household processing techniques. Therefore, mature Texas "Rio Red" grapefruits were processed by some of the common household processing practices such as blending, juicing, and hand squeezing techniques and analyzed for their phytochemical content by high performance liquid chromatography (HPLC). Results suggest that grapefruit juice processed by blending had significantly (P < 0.05) higher levels of flavonoids (narirutin, naringin, hesperidin, neohesperidin, didymin, and poncirin) and limonin compared to juicing and hand squeezing. No significant variation in their content was noticed in the juice processed by juicing and hand squeezing. Ascorbic acid and citric acid were significantly (P < 0.05) higher in juice processed by juicing and blending, respectively. Furthermore, hand squeezed fruit juice had significantly higher contents of dihydroxybergamottin (DHB) than juice processed by juicing and blending. Bergamottin and 5-methoxy-7 gernoxycoumarin (5-M-7-GC) were significantly higher in blended juice compared to juicing and hand squeezing. Therefore, consuming grapefruit juice processed by blending may provide higher levels of health beneficial phytochemicals such as naringin, narirutin, and poncirin. In contrast, juice processed by hand squeezing and juicing provides lower levels of limonin, bergamottin, and 5-M-7-GC. These results suggest that, processing techniques significantly influence the levels of phytochemicals and blending is a better technique for obtaining higher levels of health beneficial phytochemicals from grapefruits. Practical Application: Blending, squeezing, and juicing are common household processing techniques used for obtaining fresh grapefruit juice. Understanding the levels of health beneficial phytochemicals present in the juice processed by these techniques would enable the consumers to make a better choice to obtain high level of these compounds.

Comparison of the Effects of Blending and Juicing on the Phytochemicals Contents and Antioxidant Capacity of Typical Korean Kernel Fruit Juices

“…This is consistent with previously reported data. Uckoo et al (12) reported that the concentration of ascorbic was significantly higher in grapefruit juice that had been processed by juicing, while the concentration of citric acid was significantly higher in grapefruit juice that had been processed by blending. As shown in Table 1, the most abundant organic acid present in the apple juices was malic acid (3,744.5∼4,091.6 μg/mL), and the least abundant organic acid present in the apple juices was ascorbic acid (38.2∼112.2 μg/mL).…”

“…Determination of the effect of different household processing techniques on fruit phytochemical levels would be of interest to consumers seeking to obtain higher levels of these compounds (10,11). Previous studies report that juice extraction methods significantly influence chemical components levels and antioxidant activity of fruit (11,12). Rajasekar et al (11) suggest that blending is more efficient than mechanical press juice extraction at preserving the overall physico-chemical characteristics of pomegranate juice.…”

“…The outer rind of the fruit is frequently leathery and not consumable. Hence, when preparing fresh juice for consumption, most fruits are either peeled and blended or cut in half and the edible segments are juiced (12). However, recent studies suggest that use of the fruit peel can increase the amount of total polyphenols and flavonoids in the juice products (13,14).…”

“…Thus, the removal of peels may result in a significant loss of constituents beneficial to human health. In recent years, many large-scale studies have been conducted on clarified fruit juice from a wide variety of sources (3,10,12). …”

Cytotoxic Effects of Phytophenolics from Caesalpinia mimosoides Lamk on Cervical Carcinoma Cell Lines through an Apoptotic Pathway

“…Each 20 μl fraction was injected into a HPLC column (Luna C18; 15 cm x3.0 mm; Phenomenex, USA) by using a modified method of Uckoo et al, 2012(Uckoo et al, 2012. Gradient elution was conducted at a flow rate of 1.5 ml/min using methanol and 0.5% phosphoric acid at ratios of 5: 95, 70:30, 90:10, and 5:95 at 0-17, 17-18, 18-20.5 and 20.5-25 min, respectively.…”