Bioactive components,physicochemical and starch characteristics of different parts of lotus (Nelumbo nucifera Gaertn.) plant: a review

Lotus plant parts such as flower, seed, root, leaf and stem or rhizome have a great potential for food and non-food applications. This review recognises the nutritional and therapeutic benefits, functional behaviour, post-harvest processing and applications of the lotus plant. Its unique bioactive constituents, such as phenolic compounds, alkaloids, flavonoids and essential oils, have proven efficacy in improvement of health. The good amount of dietary fibre, starch, vitamins and minerals suggest that it has potentially an appropriate opportunity for future valorisation and application as functional additive and ingredient in the food industry. As a functional ingredient for use in the food industry like flour in bakery industry, as an antioxidant, for incorporation in baby foods, extruded products, beverages etc. there is a need to study the characteristics of lotus plant especially the rhizome part.     

Complexation of starch and phenolic compounds during food processing and impacts on the release of phenolic compounds

Phenolic compounds can form complexes with starch during food processing, which can modulate the release of phenolic compounds in the gastrointestinal tract and regulate the bioaccessibility of phenolic compounds. The starch–phenolic complexation is determined by the structure of starch, phenolic compounds, and the food processing conditions. In this review, the complexation between starch and phenolic compounds during (hydro)thermal and nonthermal processing is reviewed. A hypothesis on the complexation kinetics is developed to elucidate the mechanism of complexation between starch and phenolic compounds considering the reaction time and the processing conditions. The subsequent effects of complexation on the physicochemical properties of starch, including gelatinization, retrogradation, and digestion, are critically articulated. Further, the release of phenolic substances and the bioaccessibility of different types of starch–phenolics complexes are discussed. The review emphasizes that the processing-induced structural changes of starch are the major determinant modulating the extent and manner of complexation with phenolic compounds. The controlled release of complexes formed between phenolic compounds and starch in the digestive tracts can modify the functionality of starch-based foods and, thus, can be used for both the modulation of glycemic response and the targeted delivery of phenolic compounds.     

Degradation of starch in feed concentrates by enzymes,rumen fluid and rumen enzymes

The degradation of starch from various feedstuffs was investigated with rumen fluid, α-amylase, pancreatin and a freeze-dried, cell-free preparation of rumen fluid. Rumen fluid was taken from either a hay-fed cow or a concentrate-fed cow. It was shown that incubations with rumen fluid at a constant pH of 6·5 gave a higher degradation of starch than those with a decreasing pH. The degree of starch degradation varied widely for the 21 feedstuffs investigated. Sorghum, maize and millet degraded slowly whereas tapioca showed fast degradation. Processed feedstuffs showed a higher level of degradation than unprocessed ones. The use of enzymes did not allow an accurate prediction of starch degradation by rumen fluid. However, this was made possible by the use of a freeze-dried, cell-free preparation of rumen fluid. Scanning electron microscopic observations showed that for the degradation of starch granules additional enzymes, present in rumen fluid, are necessary.     

In vitro evaluation of digestive enzyme inhibition and antioxidant effects of naked oat phenolic acid compound (OPC)

This research was focused on digestive enzyme inhibition and antioxidant properties of naked oat phenolic acid compound (OPC). Free and bound phenolic acid were separated from ethyl acetate fraction, n-butanol fraction and aqueous fraction. The interactions between OPC and main digestive enzymes (α-amylase, α-glucosidase, pepsin and trypsin) were studied. It was shown that the semi-purified bound phenolic acid (semi-purified by AB-8 column) has a competitive alpha-glucosidase inhibitor, while OPC of the organic extract fraction exhibited the characteristics of a mixed inhibitor. Bound phenolic-n-butanol fraction (IC₅₀ = 98.39 ± 0.89 µg mL⁻¹) had the strongest ability to scavenge the 1,1-diphenyl-2-picrylhydrazyl (DPPH). Additionally, the starch hydrolysis degree of n-butanol extraction naked oat phenolic compound was significantly lower than other fractions in vitro. The integrated results suggested that OPC could be considered as potential healthy factor to control postprandial blood glucose, and the mechanism maybe via anti-digestion, antioxidation and interaction with diabetes-related starch.     

Phenolic characterization,antioxidant activities,and inhibitory effects of Physalis angulata and Newbouldia laevis on enzymes linked to erectile dysfunction

This study reports the phenolic composition, antioxidant activity, and capacity of Physalis angulata and Newbouldia laevis leaves to inhibit enzymes (phosphodiesterase-5′ [PDE-5′], arginase, acetylcholinesterase [AChE], and angiotensin-I converting enzyme [ACE]) linked to erectile dysfunction. High-performance liquid chromatography–diode array detector analysis of the aqueous extracts revealed the presence of phenolic acids (caffeic, ellagic, chlorogenic, and gallic acids) and flavonoids (quercetin, rutin, isoquercitrin, kaempferol, and quercitrin). N. laevis exhibited significantly higher inhibitory effects on PDE-5′, arginase, and ACE activities compared to P. angulata. There was no significant (P < 0.05) difference in the AChE inhibitory activities of both extracts. Furthermore, P. angulata exhibited lower radical scavenging and chelating abilities compared to N. laevis. These findings revealed that P. angulata and N. laevis leaves are good candidates for the development of functional foods with potentials to improve erectile function.     

Effects of high hydrostatic pressure on enzymes, phenolic compounds, anthocyanins, polymeric color and color of strawberry pulps

BACKGROUND: Changes in activity of polyphenol oxidase (PPO), peroxidase (POD) and β‐glucosidase, individual phenolic compounds other than anthocyanins, total phenols, monomeric anthocyanins, polymeric color and instrumental color of strawberry pulps were assessed after high hydrostatic pressure (HHP) (400–600 MPa 5–25 min^?1) at room temperature. RESULTS: β‐Glucosidase was activated by 4.7–16.6% at 400 MPa 5–25 min^?1 and inactivated by 8.0–41.4% at 500 or 600 MPa. PPO and POD were inactivated at all pressures, the largest reduction in activity being 41.4%, 51.5% and 74.6%, respectively. The individual phenolic compounds and total phenols decreased at 400 MPa, but total phenols increased at 500 or 600 MPa. However, the monomeric anthocyanins, polymeric color and redness (a*) exhibited no change. HHP induced a decrease in lightness (L*) and an increase in yellowness (b*) at 400 MPa, but no significant alteration in L* value and b* value at 500 or 600 MPa was observed; this was attributed to higher residual activity of PPO, POD and β‐glucosidase at 400 MPa. Total color difference (ΔE) was ≥ 5 at 400 MPa and ?3 at 500 or 600 MPa. CONCLUSION: HHP effectively retained anthocyanins, phenolic compounds and color of strawberry pulps, and partly inactivated enzymes. Copyright © 2011 Society of Chemical Industry     

Red clover (Trifolium pratense L.) isoflavones: determination of concentrations by plant stage,flower colour,plant part and cultivar

BACKGROUND: Red clover (Trifolium pratense L.), a widely used fodder, has recently received considerable interest as a valuable source of isoflavones for many health‐related applications. The aim of this study was to analyse the concentrations of four isoflavones, daidzein, genistein, formononetin and biochanin A, in extracts of leaves, stems, roots and different coloured flowers from red clover by high‐performance liquid chromatography and to determine the antifungal activities of the extracts. RESULTS: Among greenhouse‐grown samples the highest amounts of daidzein and genistein were found in petioles (0.11–0.28 and 0.30–0.54 mg g^?1 respectively), while leaves were rich in formononetin and biochanin A (5.57–9.05 and 10.94–14.59 mg g^?1 respectively). High formononetin concentrations were found in roots, but very little biochanin A. Among field‐grown samples the highest concentrations of daidzein and genistein were detected in stems collected in August (0.24 and 0.55 mg g^?1 respectively), while the highest amounts of formononetin and biochanin A were found in young leaves collected in June (7.47 and 9.69 mg g^?1 respectively). Most of the extracts inhibited the growth of Drechslera teres, while the root extract showed the strongest effect against Microdochium nivale. CONCLUSION: High levels of bioactive compounds found not only in inflorescences but also in roots, leaves and stems suggest that red clover may be an inexpensive and valuable resource for many applications. Copyright © 2007 Society of Chemical Industry     

Structural and chemical analysis of resistant starch effected by pre-treatments,cooking methods,reheating and storage condition in parboiled germinated brown rice (Oryza sativa)

Resistant starch (RS) content could be altered by the processing method, including pre-treatment, cooking method and storage conditions. This study determined the influence of RS formation in white rice (WR), brown rice (BR) and parboiled germinated brown rice (PGBR) as affected by various pre-treatment and processing conditions. This is the first report to chemically and structurally analyse WR, BR and PGBR of the same rice variety using X-ray diffraction, DSC and SEM. The results showed that the PGBR prepared by a non-soaking process cooked with steaming and stored cold contained RS content (92.1 mg/g, wet basis) followed by BR processed by soaking, steamed and then stored cold (91.8 mg/g, wet basis). The formation of RS3 as not affected by the parboiling and germination process compared to WR and BR. Reheating reduced resistant starch content by changing the RS structure conformation from crystalline to amorphous under higher temperatures. Moreover, the scanning electron microscope revealed that WR, BR and PGBR of the same rice variety show similar starch granule and microstructure patterns but slightly different in thermal conductivity value.     

Effects of different osmo‐dehydrofreezing treatments on the volatile compounds,phenolic compounds and physicochemical properties in mango (Mangifera indica L.)

The influences of different osmotic solution pretreatments (sucrose, glucose and maltose with concentration of 45%) on the volatile compounds, phenolic compounds and other physicochemical parameters in frozen mangoes were studied. Volatile and phenolic compounds were measured using SPME/GC‐MS and HPLC method, respectively. The results revealed that compared with untreated frozen mango, some volatile compounds (e.g. alcohols, aldehydes and some terpenes and esters) increased significantly and there were more compounds identified in osmo‐dehydrofrozen samples. These changes positively affected mango aroma and resulted in higher sensory scores for osmo‐dehydrofrozen samples. In addition, data on phenolic compounds showed that dehydrofrozen samples pretreated in glucose and sucrose had higher ρ‐hydroxybenzoic acid and quercetin contents, respectively, while samples pretreated in maltose showed higher ρ‐coumaric acid and sinapic acid contents compared with untreated frozen samples. The current work indicates that osmo‐dehydrofreezing can improve the retention of phenolic and aromatic compounds in frozen mango.     

高压脉冲电场对食品微生物、酶及成分的影响

高压脉冲电场加工是一种非热杀菌技术,是指在高电场强度、短脉冲和温和的温度下处理食品。与传统的热杀菌比较,它具有很多优点,不仅能杀死微生物钝化酶类,而且能保持食品的营养成分和新鲜度。本文综述了高压脉冲电场对食品的杀菌效果、杀菌机制、影响杀菌的因素以及对食品中酶类和成分的影响。      

Textural Characteristic,Antioxidant Activity,Sugar, Organic Acid,and Phenolic Profiles of 10 Promising Jujube (Ziziphus jujuba Mill.) Selections

Abstract: Ten promising jujubes were analyzed for textural characteristic (hardness), antioxidant activity, sugar, organic acid, and phenolic profiles. Total phenolic content (TP) measured by Folin–Ciocalteu method ranged from 275.6 to 541.8 mg of gallic acid equivalents per 100 g fresh weight (mg GAE/100 g FW). Four sugars (rhamnose, fructose, sucrose, and glucose), 3 organic acids (malic, citric, and succinic acids), and 11 phenolic compounds (gallic acid, protocatechuic acid, cinnamic acid, chlorogenic acid, caffeic acid, ferulic acid, ellagic acid, catechin, epicatechin, rutin, and quercetin) were identified and quantified by high‐performance liquid chromatography in jujube fruits. The results showed that ascorbic acid and proanthocyanidins contents were positively correlated with hardness, and antioxidant activity was well correlated with TP content. Among 10 jujube cultivars, Zizyphus jujuba cv. Qingjianmuzao is good for direct consumption containing high levels of total soluble solids, total sugars, fructose, and glucose, while Zizyphus jujuba cv. Jiaxianmuzao could be an important dietary source of natural antioxidants. Practical Application: Genotype is the main factor influencing the composition of bioactive compounds in jujubes. Zizyphus jujuba cv. Qingjianmuzao is good for direct consumption, while Zizyphus jujuba cv. Jiaxianmuzao could be an important dietary source of natural antioxidants for prevention of diseases caused by oxidative stress.     

Characterisation of flour, starch and fibre obtained from sweet potato (kumara) tubers, and their utilisation in biscuit production

Sweet potato (kumara) tubers of differing colours (orange, red and white) were used to produce tuber flour, a purified starch fraction and an isolated fibre extract. The fractions from each tuber colour were added into a biscuit mixture, and the effects of tuber source and fraction composition were observed in relation to the physico-chemical characteristics of biscuits. Addition of sweet potato flour and fibre fractions to white wheat flour significantly reduced the pasting properties (peak and final viscosity) of the resulting gels by up to seven-fold compared with the control wheat flour gel (as determined by the Rapid Visco Analyser). The addition of sweet potato starch affected the pasting properties of wheat flour–sweet potato starch mixes to a lesser extent. Biscuit texture (force required to cause a biscuit to fracture) was significantly reduced with the incorporation of sweet potato fibre into the biscuit dough preparation, this was linked to a reduction in biscuit thickness and spread ratio. However, the addition of sweet potato flour and starch resulted in biscuits of similar firmness as the control biscuits.     

Phenolic Compounds,Volatiles, and Sensory Characteristics of Twelve Sweet Cherry (Prunus avium L.) Cultivars Grown in Turkey

The paper reports the phenolic, anthocyanin, and volatile compounds and sensory characteristics of 12 cultivars of sweet cherries including cvs. Belge, Bing, Dalbasti, Durona di Cesena, Lambert, Merton Late, Starks Gold, Summit, Sweetheart, Van, Vista, and 0–900 Ziraat. Eight individual phenolic compounds were determined by the HPLC‐DAD method. Among these cherries, cvs. Bing, Durona di Cesena, and Lambert contained higher levels of total individual phenolic compounds than the other cultivars. Six anthocyanins were detected in cherries and cyanidin‐3‐O‐rutinoside was principal and it was the highest level in cv. Bing. The major volatiles found were 1‐hexanol, (E)‐2‐hexen‐1‐ol, benzylalcohol, hexenal, (E)‐2‐hexenal, and benzaldehyde. Sensory evaluation of the cherries showed that cvs. Belge, Bing, Dalbasti, and Summit have higher textural and flavor scores than others. It was concluded that the same compounds for phenolic or volatiles profiles of sweet cherries were similar in qualitative; however, quantitative differences were observed in these cultivars.