Rana Muhammad Aadil

Effects of ultrasound treatments on quality of grapefruit juice

Sonication is recognised as a potential technique for improvement in the quality of fruit juices. This study was initiated with the objective of evaluating the effect of sonication treatments on some important quality parameters of grapefruit juice such as physico-chemical (pH, acidity and °Brix), Hunter colour values (L(*), a(*) and b(*)), cloud value, electrical conductivity, total antioxidant capacity, DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, ascorbic acid, total phenolics, flavonoids and flavonols. Sonication of grapefruit juice was done in a bath type sonicator at a frequency of 28 kHz by maintaining a constant temperature of 20 °C. Results showed that there was significant improvement in the cloud value, total antioxidant capacity, DPPH free radical scavenging activity, ascorbic acid, total phenolics, flavonoids and flavonols in all the juice samples sonicated for 30, 60 and 90 min but no changes occurred in the pH, acidity and °Brix value as compared to control. Some differences in all the colour values were also observed but overall quality of grapefruit juice was improved, suggesting that sonication technique may successfully be implemented an industrial scale for the processing of grapefruit juice.

Structure and digestibility of debranched and repeatedly crystallized waxy rice starch.

Debranched waxy rice starch was subjected to repeated crystallization (RC) treatment, and its physicochemical properties and digestion pattern were investigated. The A-type crystalline pattern of native starch was crystallized to a complex of B- and V-type patterns by debranching and RC treatment. Among the treated starches, the relative crystallinity of debranched starch reached its maximum (29.6%) after eight repetitions of crystallization. Changes in weight-average molar mass among treated starch samples were not significantly different. The repeated-crystallized starches showed higher thermal transition temperatures and melting enthalpy than that of debranched starch. As a result, slowly digestible starch (SDS) content of repeated-crystallized starches reached a very high level (57.8%). Results showed that RC treatment induced structural changes of waxy rice starch result in a great amount of SDS.

Antioxidant, antitumor and immunomodulatory activities of water-soluble polysaccharides in Abrus cantoniensis.

Abrus cantoniensis is a vegetative food in tropical areas of Asia and claimed as folk beverages and soups consumed for cleansing liver toxicants and preventing liver diseases. Polysaccharides (ACP-І and ACP-II) were extracted with hot water from A. cantoniensis, and isolated by DEAE cellulose chromatography. The chemical properties as well as antioxidant, antitumor and immunomodulatory activities of ACP-I and ACP-II were investigated. The results showed that the ACP-I (9.09kDa) contained only glucose and ACP-II (38.45kDa) consisted of rhamnose, arabinose, galactose and glucose. ACP-II exhibited higher oxygen radical absorbance capacity (ORAC) and hydroxyl radical prevention capacity (HRPC) than ACP-I with ORAC values and HRPC values of 53.42±3.32μmol Trolox equiv./g DW and 34.84±5.07μmol Trolox equiv./g DW. Besides, in the wound healing assay, ACP-II exhibited potent migration inhibitory effects on MCF-7 cells. ACP-II could also significantly stimulate the proliferation of splenocytes and thymocytes, and enhanced NO production of peritoneal macrophages. These findings suggest that the polysaccharide ACP-II in A. cantoniensis could be served as a novel potential functional food.

Combined effects of pulsed electric field and ultrasound on bioactive compounds and microbial quality of grapefruit juice

The combined effect of ultrasound (US) and pulsed electric field (PEF) was investigated on microbial load and bioactive compounds of grapefruit juice. Grapefruit juice was PEF treated (flow rate: 80 ml/min, pulse frequency: 1 kHz, 20 kVcm−1 electric field strength, temperature: 40 °C, time: 600 μs) followed by US treatment in an ultrasonic bath cleaner radiating 600 W at frequency of 28 KHz and 20 °C for 30 min. PEF and US treatment resulted in a significant reduction in microbial load as compared to the control group. Using combined (PEF + US) treatment, carotenoids, lycopene, anthocyanin contents, and total antioxidant activity were increased from 0.84 μg/ml, 0.32 μg/ml, 1.37 mg/L, and 177.48 ascorbic acid equivalent µg/g (control) to 1.26 μg/ml, 0.92 μg/ml, 1.68 mg/L, and 262.32 ascorbic acid equivalent µg/g, respectively. The findings demonstrated that PEF + US could be successfully used for preserving bioactive compounds in grapefruit juice while improving the microbial quality for a better shelf-life. Practical applications In recent years, nonthermal techniques, such as sonication and PEF or combination of these are used for the inactivation of microorganism and preserving the bioactive compounds of different juices. The results of the present study revealed that combined treatment (PEF + US) could improve the antioxidant activity, total phenolics, flavonols, flavonoids, lycopene, and total carotenoids. The findings of this study suggested that PEF + US has a potential to improve the quality of grapefruit juice and may be employed for the processing of grapefruit juice at industrial scale.

The efficiency and comparison of novel techniques for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis

The efficiency of various techniques pulsed electric field (PEF), ultrasound (US), high-pressure microfluidisation (HPMF), hydrochloric acid (HCl) and ionic liquids (ILs) for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis was compared. The results indicated that ILs, HCl and HPMF treatment were shown the most efficient for cell disruption with more than 80% astaxanthin recovery. While the cell wall integrity of H. pluvialis cyst cell was less affected by US and PEF treatment. It was found that imidazolium-based ILs showed the greater potential for cell disruption than pyridinium-based and ammonium-based ILs. Among all the ILs examined, 1-butyl-3-methylimidazolium chloride ([Bmim] Cl) exhibited efficient cell disruption and capability of astaxanthin recovery at mild condition (pretreatment with 40% IL aqueous solution at 40 °C, followed by extraction with methanol at 50 °C) without extensive energy consumption and special facility requirement. In addition, recyclability of ILs was excellent.

Effect of Storage on Fruit Bioactives

Fruit is considered healthy food because of the presence of several health-promoting bioactive compounds. These phytochemicals play a vital role in combating various metabolic ailments like cardiovascular complications, hypertension, hypercholesterolemia, inflammation, diabetes, oxidative stress, etc. However, these functional components are affected by different processing and storage conditions. Accordingly, the current chapter is aimed at providing an overview regarding the impact of different storage conditions (cold storage, controlled atmospheric storage, modified atmospheric storage, hypobaric storage, and hyperbaric storage) on the availability of bioactive substances in fruit. Additionally, the effects of improper postharvest handling and transport on fruit quality are also discussed in this manuscript. Furthermore, the chapter also highlights the changes in different quality parameters of fruit subjected to various storage conditions.