Two Endogenous Substrates for Polyphenoloxidase in Pericarp Tissues of Postharvest Rambutan Fruit

Abstract: The catalytic oxidation of phenolic substrates by polyphenoloxidase (PPO) causes pericarp browning of postharvest rambutan fruit. In the present study, PPO and its endogenous substrates were extracted from rambutan pericarp tissues (RPT). The substrate extracts were sequentially partitioned with ethyl acetate and n-butanol. The analysis of total phenolic content showed that the most phenolic compounds were distributed in ethyl acetate fraction. By high-performance liquid chromatography (HPLC), (−)-epicatechin (EC) and proanthocyanidin A2 (PA2) were identified from this fraction. After reacting with rambutan PPO, EC turned brown rapidly within 10 min, indicating that it was a significant endogenous substrate. Although PA2 could also be oxidized by the PPO, it turned brown very slowly. In addition, because EC and PA2 were continually catalyzed into browning products by PPO during storage of the fruit at 4 and 25 °C, their contents in RPT gradually declined with the extended storage time. It was further observed that both substrate contents in rambutan fruit storing at 25 °C decreased more rapidly than that storing at 4 °C, suggesting that low temperature inhibited the catalytic oxidation of substrates so as to slow down pericarp browning. Practical Application: Pericarp browning is a serious problem to storage and transport of harvested rambutan fruit. A generally accepted opinion on the browning mechanism is the oxidation of phenolic substrates by PPO. Ascertaining PPO substrates will effectively help us to control enzymatic reaction by chemical methods so as to delay or even prevent pericarp browning of harvested rambutan fruit.     

In vitro antioxidant activity and phenolic profiles of tropical fruit by-products

Peel and seeds of red-skinned passion fruit, mango, longan, rambutan, white-flesh and red-flesh dragon fruit were screened for their in vitro antioxidant activity, and determination of a detailed profile of phenolic compounds. Rambutan peel and mango seed extracts exhibited the highest total phenolic content and antioxidant activities (DPPH, ABTS and FRAP values). By using UPLC-QTOF-MS/MS analysis, the profiles of soluble and bound phenolics in the fruit by-products were obtained. Ellagic acid, geraniin, quercetin hexoside, gallic and galloyshikimic acid were predominant in rambutan peel, whereas, mangiferin, ellagic acid and galloy(di)glucoside were the major phenolic compounds in mango seed. Main phenolic compounds in longan peel were ellagic acid, galloyldiglucoside, and gallic acid, while in dragon fruit peel this was isorhamnetin glycoside, isorhamnetin glucorhamoside. Meanwhile, rutin and quercetin hexoside were predominant in passion fruit peel. These findings contribute significantly to the database of phenolic profiles of by-products of tropical fruits.     

The development of fruit‐based functional foods targeting the health and wellness market: a review

Functional foods and their health benefits beyond individual nutrients present challenges to the traditional ‘nutrition’ approach to foods. Epidemiological studies suggest that regular or increased consumption of fruits may promote general health and well‐being as well as reduce the risk of chronic diseases. Therefore, a broad range of research amongst academic, industry and government institutes has been stimulated in attempts to add the goodness of fruits into popular consumer foods. This article provides a brief overview of the research opportunities in the emerging functional foods area, with an emphasis on fruit‐derived products. Based on recent research in the fruit‐based functional food area, a structured approach for designing and developing functional finished products is presented. Included are the technical challenges and their associated solutions during food design, formulation, processing and storage. A consumer‐oriented food product development process is highlighted. Controlling the interactions among the targeted bioactives and other food components during food processing, handling and storage is the key to ensure that a stable and appealing functional food is produced. Manipulating the beneficial synergies among food ingredients, and among food formulation and processing methods, has the potential to lead to substantial food innovations.     

Bioactive phytochemicals, nutritional value, and functional properties of cape gooseberry (Physalis peruviana): An overview

Exotic fruits play an important role in nutrition as an excellent base for low calorie and dietetic products. Highly valued for its unique flavor, texture and color, recent research has shown cape gooseberry (Physalis peruviana) to be high in many beneficial compounds. The diversity of functional applications to which P. peruviana can be put gives this fruit great importance. The food industry has used cape gooseberry in different products including beverages, yogurts and jams. With the rapidly growing popularity of this unique fruit it is important to have a comprehensive reference for its nutritional benefits. This review provides a valuable source for current knowledge on bioactive phytochemicals and further development of P. peruviana for functional foods as well as nutraceutical and pharmaceutical industries.     

Antidiabetic Activity of Durian (Durio Zibethinus Murr.) and Rambutan (Nephelium Lappaceum L.) Fruit Peels in Alloxan Diabetic Rats

The present study was carried out to evaluate the in alloxan (150 mg/kgb.wt) induced diabetic rats. The ethanolic extract of Durian (Durio zibethinus Murr.) and rambutan (Nephelium lappaceum L.) fruit peels administered orally to the diabetic rats for 11 days, produced significant decrease in the level of blood glucose. The highest percentage reduction in blood glucose levels were shown of rambutan fruit peels extract with dose 500 mg/kgb.w and the value of persentage reduction were 61.76±4.26%.     

Development of New Product: Rambutan Pulpy Juice

This study aimed to know the effect of adding pulp in rambutan fruit juice on the characteristics of rambutan juice during storage. Research using the CRD, the treatment were kind of pulp (mandarin and rambutan) and pulp concentration (5%, 7.5%, and 10%). The results showed that the addition of pulp significantly affect the characteristics of rambutan juice (pH, vitamin C, total acid) during storage. Pulpy juice with the most prefered was addition of rambutan pulp as much as 7.5% (w/v) and the addition of citrus pulp as much as 7.5% (w/v) with the score of 3-4 (moderate like - like).     

无花果营养成分及生物活性研究进展

无花果是一种药食两用型水果,口感酸甜、肉质软糯,深受消费者喜爱。无花果富含糖、氨基酸、多酚等营养成分,具有很高的营养价值。无花果具有抗氧化、抗肿瘤、降血脂等生物活性,是开发功能性食品的优质资源。本文对无花果的营养成分进行介绍,分析其抗氧化、降血脂、抗肿瘤、抗炎及抗菌等方面的生物活性,并对无花果的研究方向进行展望,旨在为无花果功能性食品的开发和产业化提供理论依据。     

Consumers’ changing attitudes towards functional foods

In our earlier research, seven dimensions reflected consumers’ reported willingness to use functional foods. The aims of this study were (1) to further develop these attitude measurements into a shorter and more feasible format (2) to explore whether these shorter attitude scales predict consumers’ reported willingness to use functional products and (3) to monitor consumers’ attitudes towards functional foods over a period of 2.5 years. Two data sets were collected in 2002 and 2004 (n = 1156 and n = 1113, respectively). In 2002, seven dimensions observed in 2001 were partly merged and three measurements were constructed: Reward from using functional foods, Necessity for functional foods and Confidence in functional foods. When these were used for measuring consumers’ attitudes in 2004, four dimensions were found: Reward from using functional foods, Necessity for functional foods, Confidence in functional foods and Safety of functional foods. Changes in the factor structure indicate that the basis of the attitudes towards functional foods is not stable. Men and women did not differ in their attitudes towards functional foods. Minor differences between age and education groups were practically non-existent. In both data sets, the best predictors for willingness to use functional foods were the perceived reward and the necessity for such foods. The dimensions, however, predict reported behaviour differently depending on the target product. During the study, the influence of the perceived necessity on the willingness to use functional foods became weaker. The functional foods in Finland may be approaching the status of conventionally healthy foods.     

不同预冷方式对红毛丹贮藏品质的影响

比较冰水预冷、冷库预冷、压差预冷3种预冷方式对红毛丹低温贮藏品质的影响,获得最佳预冷方式。以海南省红毛丹"保研7号"为材料,经过3种预冷方式处理果实,6±1℃贮藏16 d,分别于0,4,8,12和16 d进行8个品质指标比较。结果显示,压差预冷保持较高好果率,明显抑制果皮中相对电导率增加和PAL活性,在16 d时分别比CK组的下降28.77%和11.33%。果肉中的丙二醛、可滴定酸、POD活性明显降低,在16 d时分别比CK组的下降22.86%,20.88%和32.47%,保持较好品质。压差预冷后的果实贮藏品质最好,冷库预冷效果次之,冰水预冷效果不明显,可为红毛丹冷链物流应用提供参考。     

Stability of Pycnogenol® as an ingredient in fruit juices subjected to in vitro gastrointestinal digestion

BACKGROUND: The enrichment of fruit juices with concentrated polyphenolic extracts is an expedient strategy to compensate possible phenolic loss through gastrointestinal processing. Pycnogenol®, a standardised procyanidin‐rich extract from pine bark, has been proposed as a potential candidate for polyphenol enrichment of foods. In this study the effects of in vitro digestion on the phenolic profile of fruit juices enriched with Pycnogenol® were investigated. RESULTS: After in vitro digestion the level of detectable total phenolic compounds (expressed as gallic acid equivalent) was higher in both pineapple and red fruit juices enriched with Pycnogenol® than in non‐enriched commercial juices. Five phenolic monomeric compounds were identified by high‐performance liquid chromatography, namely chlorogenic acid, caffeic acid, ferulic acid, gallic acid and taxifolin, the last two being predominant. In vitro digestion of both Pycnogenol®‐enriched pineapple and red fruit juices led to a significant (P < 0.05) increase in detectable chlorogenic and ferulic acids, indicating that hydrolysis of more complex molecules occurs. On the other hand, in vitro digestion of non‐enriched juices was associated with a decrease in gallic and caffeic acids in pineapple juice and with a decrease in ferulic acid in red fruit juice. In no case did in vitro digestion increase the amount of detectable phenolic compounds in non‐enriched juices. CONCLUSION: The stability of Pycnogenol® after in vitro gastrointestinal digestion makes it a good choice for phenolic enrichment of fruit juices. Copyright © 2010 Society of Chemical Industry     

Potential of Selected Tropical Fruit Peels as Dietary Fiber in Functional Foods

The peels of rambutan, durian, santol, longan, longong, Kaeo mango, and Chok Anan mango were evaluated for their potential to be used as dietary fiber for food enrichment. All dietary fiber samples prepared from selected fruit peels showed high content of total dietary fiber (52–84 g/100 g dry matter) and also exhibited the significant difference in dietary fiber quality. All dietary fiber samples were safe for consumption, which was ensured by the results of an acute toxicity test. In summary, peels of tropical fruits used in this study had a great potential to be used as low-caloric functional ingredients for dietary fiber enrichment.     

Current trends of tropical fruit waste utilization

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.     

海巴戟天果实内生菌和多酚类成分的研究进展

海巴戟天(Morinda citrifolia),茜草科(Rubiaceae)巴戟天属(Morinda)植物,又名诺丽(NONI),在波利尼西亚已有长达2000年的食用和药用历史。海巴戟天果实中存在丰富的内生菌资源,自然发酵是其生产加工中的重要工艺,因此对果实内生菌和活性成分的研究具有重要意义。本文综述了海巴戟天果实中内生微生物的种类以及主要的活性成分-酚类成分的结构,主要包括蒽醌类、香豆素类、木脂素类、黄酮类、酚酸及其他酚类,归纳了海巴戟天果实具有的多种生理活性,主要包括抑菌、对肝损伤的保护、抗癌、抗氧化、对心血管保护以及增强免疫等。为研究海巴戟天果实的功能食品和药品提供一定的理论借鉴,有利于更广泛和有效地利用海巴戟天果实资源,旨在为今后更深入研究食品的自然发酵工艺提供借鉴和参考。     

Functional compounds from olive pomace to obtain high‐added value foods – a review

Olive pomace, the solid by‐product from virgin olive oil extraction, constitutes a remarkable source of functional compounds and has been exploited by several authors to formulate high value‐added foods and, consequently, to foster the sustainability of the olive‐oil chain. In this framework, the aim of the present review was to summarize the results on the application of functional compounds from olive pomace in food products. Phenolic‐rich extracts from olive pomace were added to vegetable oils, fish burgers, fermented milk, and in the edible coating of fruit, to take advantage of their antioxidant and antimicrobial effects. Olive pomace was also used directly in the formulation of pasta and baked goods, by exploiting polyunsaturated fatty acids, phenolic compounds, and dietary fiber to obtain high value‐added healthy foods and / or to extend their shelf‐life. With the same scope, olive pomace was also added to animal feeds, providing healthy, improved animal products. Different authors used olive pomace to produce biodegradable materials and / or active packaging able to increase the content of bioactive compounds and the oxidative stability of foods. Overall, the results highlighted, in most cases, the effectiveness of the addition of olive pomace‐derived functional compounds in improving nutritional value, quality, and / or the shelf‐life of foods. However, the direct addition of olive pomace was found to be more challenging, especially due to alterations in the sensory and textural features of food. © 2020 Society of Chemical Industry     

Dietary intake exposure to sulphites in Italy - analytical determination of sulphite-containing foods and their combination into standard meals for adults and children

The theoretical risk of exceeding the Acceptable Daily Intake (ADI) for sulphites has mostly been examined on the basis of a worst-case scenario. In order to examine the real situation the determination of residue sulphite levels in ready-to-consume foods is required. The aim of this paper is to assess the actual sulphite content of diets obtained from a combination of realistic meals high in sulphite-containing foods. Food products available in Italy containing added sulphites were identified. Overall, 211 samples of foods and beverages (including 85 samples of wine) were collected. The determination of sulphite residues was carried out on the foods which were prepared according to normal domestic practice. It was shown that the diets obtained from these foods would lead to an intake of 23mg/day in children and 50mg/day in adults (both slightly above the ADI for respectively a 30kg child and a 60kg adult). Among all sulphite-containing foods, the highest contributors to the intake were dried fruit and wine, both ingested without further treatment. The analysis of specific consumption data confirmed the existence of a risk of exceeding the ADI related to sulphite residue levels in wine.     

Distinctive exotic flavor and aroma compounds of some exotic tropical fruits and berries: a review

The characteristic flavor of exotic tropical fruits is one of their most attractive attributes to consumers. In this article, the enormous diversity of exotic fruit flavors is reviewed. Classifying some of the exotic fruits into two classes on the basis of whether esters or terpenes predominate in the aroma was also attempted. Indeed, as far as exotic tropical fruits are concerned, the majority of fruits have terpenes predominating in their aroma profile. Some of the fruits in this group are the Amazonian fruits such as pitanga, umbu-caja, camu-camu, garcinia, and bacuri. The ester group is made up of rambutan, durians, star fruit, snake fruit, acerola, tamarind, sapodilla, genipap, soursop, cashew, melon, jackfruit, and cupuacu respectively. Also, the role of sulphur-volatiles in some of the exotic fruits is detailed.     

Comparison of antioxidant capacities and cytotoxicities of certain fruit peels

This work was undertaken to explore the potential of fruit waste materials as sources of powerful natural antioxidants. The peels of eight kinds of fruits commonly consumed and grown in Thailand were used. The ethanolic fruit peel extracts were subjected to the scavenging tests of DPPH and ABTS radicals. Results from both assays were in good agreement that the top three markedly high free radical-scavenging power was from the peel extracts of Punica granatum (pomegranate), Nephelium lappaceum (rambutan), and Garcinia mangostana (mangosteen). The IC₅₀ values to quench the DPPH free radicals of these three extracts were 0.003, 0.006, and 0.023 mg/ml and the trolox equivalent antioxidant capacity (TEAC) values from ABTS assay were 4.066, 3.074, and 3.001 mM/mg, respectively. The extract of mangosteen peel showed moderate toxicity to Caco-2 cells and high toxicity to peripheral blood mononuclear cells (PBMC) with the IC₅₀ values of 32.0 and 4.9 μg/ml, respectively. Pomegranate peel extract stimulated Caco-2 cell and PBMC proliferation with the ED₅₀ of 4.7 and 44.4 μg/ml, respectively. Peel extract of rambutan exhibited extremely high value of IC₅₀ (>100 μg/ml) against both cell types indicating non-toxic activity to the cells. It was concluded that the peel of rambutan may be considered potentially useful as a source of natural antioxidants for food or drug product because of its high antioxidant activity and non-toxic property to normal cells.     

柠檬烯抑菌机理及其在果蔬保鲜中应用的研究进展

果蔬在采后贮藏保鲜过程中极易被微生物侵染而腐烂变质,这严重影响其货架期与质量安全,甚至较大经济损失。为此,研发具有抑菌效果显著、生物安全性高的天然防腐剂一直是果蔬保鲜领域学者关注的热点。柠檬烯因具有广谱抑菌性且安全性佳,已被广泛应用于果蔬保鲜领域。本文主要论述了柠檬烯的抑菌机理及在果蔬保鲜领域中的应用,并讨论了其未来的发展方向,以期为柠檬烯在果蔬及其他食品保鲜中的进一步研究和应用提供参考。     

Jackfruit and Its Many Functional Components as Related to Human Health: A Review

Abstract: Jackfruit (Artocarpus heterophyllus Lam.) is an ancient fruit that is widely consumed as a fresh fruit. The use of jackfruit bulbs and its parts has also been reported since ancient times for their therapeutic qualities. The beneficial physiological effects may also have preventive application in a variety of pathologies. The health benefits of jackfruit have been attributed to its wide range of physicochemical applications. This review presents an overview of the functional, medicinal, and physiological properties of this fruit.     

Characteristics of fat,and saponin and tannin contents of 11 varieties of rambutan (Nephelium lappaceum L.) seed

Rambutan seed is discarded during fruit processing. However, the seed contains a considerable amount of crude fat. Hence, the objective of this study was to determine two anti-nutritional constituents, namely saponin and tannin, and to characterize the fat of the seeds of 11 varieties of rambutan fruit. Results showed that the range of crude fat content is fairly narrow (36.13–39.13 g/100 g dried seeds). The iodine value and free fatty acid content of the fat were 38.50–50.61 g I₂/100 g fat and 0.99–2.18% as oleic acid, respectively. Oleic (33.35–46.64%) and arachidic (26.03–33.27%) acids were the main fatty acids in the fat. HPLC analysis showed that the fat comprised mainly five unknown triacylglycerols (83.94–95.33%). The melting and crystallization curves showed that the fat exhibited four to nine non-distinct peaks. The complete melting and crystallization onset temperatures of the fat were 24.8–50.6°C and 24.1–39.4°C, respectively, while the melting and crystallization enthalpies of the fat ranged from 71.2 to 141.7 J/g and from 60.4 to 88.9 J/g, respectively. At 0°C, the solid fat index of the fat ranged between 87.4% and 91.6% and the fats of some varieties melted completely at human body temperature. The saponin and tannin contents of the seed were 14.27–18.96 mg soya saponin/100 g and 4.40–26.68 mg catechin equivalent/100 g, respectively. Findings showed that rambutan seed fat has potential to be used in various sectors of food industry.