Date palm fruits and their seeds are excellent sources of dietary fiber (DF). Date fruits contain 8.1–12.7 % Total DFs (of which 84–94 % is insoluble and 6–16 % soluble DF) and is very rich in phenolic antioxidants (1–2 %). Date fruit fibers are composed of cellulose and NSP. Moreover, date DF has important functional properties, such as water-holding capacity and oil-holding capacity. Date seeds contain about 15 % fiber, characterized by a high level of water-insoluble mannan fibers. It has been suggested that date fruits and seeds can be exploited in some food applications. In order to improve fiber yields, pretreatment procedures can be applied, which give excellent results in the case of date palm fibers. Date fruits are widely available in the global market, but there is still room for improvement, particularly in the revalorization of date processing waste, and secondary cultivars. The incorporation of date fruits and seeds as food ingredients would promote the presence of dates in the modern's consumer shopping basket. Present knowledge about different aspects of date DF, and suitable extraction methods and applications of date fiber (flesh and seed), will be the focus of this report.
The caking of sugar is a major problem in Japan. However, no method has been established to evaluate caking quantitatively. The purpose of this study was to investigate the powder characteristics of granulated sugar in Japan as one of the factors causing caking. The study measured crystal properties, grain size and other powder characteristics of granulated sugar. Samples were collected from four granulated sugar (GS: 500–650 µm) products and 15 fine granulated sugar (FGS: 200–500 µm) products which differed in types of grain sizes. Irregular fine particles were observed in products with a small grain size. GS showed a smaller compression degree and larger Carr index than FGS. As a result of principal component analysis, the products were divided into three groups excluding the particular products.
To develop a method for the identification of shiikuwasha (Citrus depressa Hayata) and calamondin (Citrus madurensis Lour.), trnL-trnF and trnT-trnL intergenic spacer regions of their chloroplast DNA were amplified using PCR and the nucleotide sequences were determined. In each region, a single nucleotide polymorphism (SNP) site specific to the respective citrus species (shiikuwasha and calamondin) was found. For species discrimination using PCR, two forward primers containing the allele-specific SNP site at the 3′-end and a mismatched nucleotide at the 3rd base from the 3′-end were designed. The allele-specific forward primers specific to shiikuwasha and calamondin were respectively designated CiDeLF-F and CiMaTL-F. To confirm the specificity of the designed primers, PCR was carried out with DNA prepared from citrus peel or hand-squeezed juice as the template. Results showed that shiikuwasha and calamondin fruits and juices were identifiable by PCR using the allele-specific primers. Furthermore, this allele-specific PCR method can be applied to industrially processed and concentrated juice by amplifying DNA in advance.
The objectives of this study were to isolate and purify blueberry anthocyanin by combination of macroporous resin and Sephadex LH-20 and identify anthocyanin composition after isolation and purification. The static adsorption/desorption experiments of anthocyanin on ten different types of resins were compared. The results showed that the highest AB-8 macroporous resin adsorption rate of 97.73 % and desorption rate of 81.52 % from blueberry were achieved under optimal conditions (Adsorption conditions: a flow rate of feed 1.0 mL/min, anthocyanin concentration of 1.0 mg/mL, pH of 3.0; Desorption conditions: an eluent flow rate of 1.5 mL/min, ethanol concentration of 60 %, pH of 3.0). The anthocyanin purity increased 19.86-fold from 4.58 % to 90.96 % after one run treatment with macroporous resin combined Sephadex LH-20 method. Delphinidin-3-glucoside and cyanidin-3-glucoside were identified by HPLC-ESI-MS/MS. The results of this study may effectively promote the purification of anthocyanin from most blueberry varieties as well as from other plant materials.
Aqua-gas (AQG; superheated steam containing micro-droplets of hot water) was developed as a pretreatment technology before primary processing, such as sterilization, without sacrificing the material yield and maintaining qualities such as functionality. Its application to drying treatment, however, had yet to be studied. In this study, we examined its applicability to drying treatment of egoma (Perilla frutescens (L.) Bitt. var. frutescens) leaves. Results revealed that when egoma leaves were treated with AQG, they underwent a drying process that progressed with time, as was the case for treatment with superheated steam (SHS). AQG treatment produced dried leaves with a final wet weight-based water content of <10 %. We then investigated the effects of different drying methods on functional components in egoma leaves, and found that such components (e.g., α-linolenic and rosmarinic acids) were preserved during treatment with AQG, or AQG followed by SHS, at levels comparable to those by freeze drying (FD). In contrast, rosmarinic acid content was reduced after drying with SHS alone or hot air drying (HAD). In addition, egoma leaves were successfully sterilized by treatment with AQG, SHS, or AQG followed by SHS, or by steaming followed by HAD. Common bacteria remained viable after HAD treatment. Moreover, egoma leaves dried with AQG, AQG followed by SHS, or steaming followed by HAD had significantly higher DPPH radical-scavenging activity than the FD-treated product. In contrast, such activity was reduced after HAD. In addition, radical-scavenging activity correlated well with total soluble polyphenol content and polyphenol oxidase activity. These results suggest that AQG treatment shows promise as an efficient approach to completing the multiple steps generally required for drying leafy vegetables (blanching, drying, and sterilization) in one step, while preserving functional components.
The aim of this study was to investigate the potential for improving the quality of mung bean sprouts by using high hydrostatic pressure (HHP). Mung bean sprouts were subjected to HHP treatments of 200, 400, or 600 MPa at 25 °C for 10 min. Treated and untreated samples were preserved for 0–8 days at 4 °C, and then analyzed to determine changes in amino acid concentration. The total amino acid concentration of samples treated at 200 and 400 MPa increased linearly during the preservation period. The amino acid concentration of treated samples was 2–3 times higher than that of untreated samples after 4 and 8 days of preservation. Moreover, the trend of increases in amino acid concentrations was different; thus, HHP treatment might have improved not only proteolysis, but also amino acid metabolism in mung bean sprouts. Taken together, this study demonstrates that HHP treatment is an attractive method to develop value-added foods.
Despite the high nutritional value of ripe red bell pepper (RBP) juice, RBP is typically considered a bitter vegetable. This excess bitterness affects the quality of RBP juice and results in rejection by consumers. We developed a manufacturing process to remove the bitter taste of RBP juice while retaining high nutrient levels. Compared to several resins, synthetic adsorbent resins had the most pronounced debittering effects, yielding the least bitter taste and green top note, while retaining a sweet taste and flavour. In particular, a styrene-divinylbenzene adsorbent resin having relatively large pores (pore radius ≥ 250 Å) removed more than 83 % of the bitterness of RBP juice, based on the quercetin-3-O-rhamnoside content. Moreover, vitamin B6 was retained at a high level, and the basic nutritional balance did not change after the treatment. The debittering effect was correlated with resin content, implying that quercetin-related flavonoids accounted for the bitter taste of RBP juice. Thus, resin adsorption is an efficient technique for the debittering and selective retention of high-value nutrition in RBP juice.
The purpose of this study was to evaluate the vapor-phase antibacterial efficacy of garlic essential oil (GEO) and citronella essential oil (CEO) against four foodborne bacteria and their vapor-phase antibacterial mechanism against Staphylococcus aureus (S.aureus). GC-MS analysis confirmed that diallyl disulfide (29.258 %) and citronellal (36.940 %) were the major constituents of GEO and CEO, respectively. GEO and CEO at concentrations of 80 µL/L could completely inhibit the growth of all tested bacteria and the combinations of GEO with CEO displayed additive effects against the four tested bacteria with fractional inhibitory concentration index (FICI) values of 0.75 or 0.50. Furthermore, the scanning electron microscopy observations, the change of proteins concentration and catalase activity of S.aureus confirmed that the EOs impacting the membrane integrity and catalase activity of S.aureus. Thus, our study will provide a theoretical foundation for the applicability of EOs on the non-contact preservative packaging for food.
Heating vegetable oil in a microwave oven can lead to the formation of reactive free radicals, which are responsible for causing lipid oxidation. The thermo-oxidative stability of olive oil has previously been studied under microwave heating for short processing periods that simulate typical cooking times. This study compares the effect of the oxidative degradation of extra virgin olive oil (EVOO) during extended heating times under different microwave powers (150 and 500 W) or conventional heating. The results showed that intense microwave heating of EVOO significantly increased the free acidity and specific extinction coefficients (K270), and resulted in more severe loss of phenolic compounds, compared with conventional heating. Microwave treatment also resulted in higher amounts of acrolein in EVOO after a short processing period compared with conventional heating. These results demonstrate that intene microwave heating has a more severe effect on EVOO compared with conventional heating.
The color of beer, which is a typical example of the Maillard or browning reaction, is mainly attributed to melanoidins. However, as melanoidins are heterogeneous polymers formed by the Maillard reaction, there is little data on the chemical structure of the components responsible for the color of beer. To obtain chemical information on the color components of beer, we here isolated a low-molecular-weight yellow pigment from black beer and identified it using instrumental analyses and an authentic sample. As a result, the pigment was identified as perlolyrine, which is a Maillard reaction product from tryptophan; however, its contribution to the total color of beer was very low. This pigment was present in various kinds of beer at the level of 3.2–14.0 µg/100 mL.
Hyperphosphatemia is a secondary health issue that arises during chronic kidney disorder (CKD). Phosphate binders and dialysis are prescribed in later stages of CKD, although they may lead to harmful side-effects and worsen quality of life. Therefore, we examined the potential of intestinal bacteria (lactic acid bacteria and bifidobacteria) as phosphate-accumulating organisms (PAOs), whether PAO-formulated food can prevent CKD at earlier stages. Among the experimental organisms, Bifidobacterium adolescentis JCM1275 was the most effective. The effects of prebiotic and soy peptides were also evaluated where fructo-oligosaccharide was found to further enhance phosphate accumulation by B. adolescentis JCM1275, resulting in the best phosphate accumulation activity, identified in the study. Therefore, certain bifidobacteria and lactic acid bacteria strains have the potential to act as biological phosphate accumulators and contribute to the prevention of CKD pathology and improve patient outcome by care (not cure by medicines).
Protein oxidation can alter the structure of myofibrillar proteins (MPs), which further affect the MPs gelling properties. Ionic strength can influence MPs oxidation. The objective of the study was to evaluate changes in structure and gel properties of MPs induced by hydroxyl radicals (•OH) under certain ionic strength and pH. MPs were very susceptible to •OH attack under 0.5 M NaCl (pH 6.25) due to their swelling structure, resulting in higher protein oxidation level. Oxidative alternation of MPs structure had a significant influence on gel properties and microstructure. The maximum of storage modulus (G′) during the cooling stage was observed at 1.0 mM H2O2. Results of SEM confirmed that the gel had a more compact and dense structure at 1.0 mM H2O2. The results demonstrated that mild oxidative modification (H2O2 ≤ 1.0 mM) induced MPs aggregation, which was benefit to the formation of gel elastic network. However, further oxidative modification (2.5 mM ≤ H2O2 ≤ 10.0 mM) led to an excessively cross-linking of MPs, which made a negative effect on gel properties.
D-Glucosamine (GlcN) has been widely consumed as a dietary supplement because of its health benefits. However, limited information exists on the adverse effects of high-dose GlcN treatment. In this study, we investigated the effect of dietary 4 % GlcN hydrochloride on serum and cecum parameters in rats. Growth and food intake were unaffected, but serum levels of ammonia and ethanol significantly increased by GlcN (+21 % and +12 %, respectively). No changes in serum parameters, including AST, ALT, LDH, γ-GTP (indices of liver damage), and urea, were found. The GlcN intake significantly increased the weights of cecal contents (+115 %). Furthermore, supplemental GlcN significantly elevated the levels of ammonia and ethanol (+27 % and +93 %, respectively) and the number of total bacteria (+79 %), when expressed per gram of cecal contents. Our results suggest that high-dose GlcN causes adverse effects by increasing ammonia and ethanol levels and by bacterial overgrowth.
This study investigated the effect of cooking methods including steaming, blanching, microwaving, boiling, and roasting on the true retention of minerals, vitamins, and bioactive compounds in shiitake mushrooms (Lentinus edodes). The proximate composition significantly decreased after cooking. In general, the true retentions of minerals were lowest in the boiled samples. Microwaved and roasted samples showed higher true retentions of minerals than other cooking methods. Boiling resulted in the lowest true retention levels of vitamins and bioactive compounds, while roasting resulted in the higher true retention values. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities of blanched, boiled, and steamed samples decreased compared with the activities of the raw samples. However, the antioxidant activities of microwaved and roasted samples were maintained or increased. These results suggest that cooking causes changes in nutritional content that are dependent on the type of cooking method. In addition, when estimating the dietary intake of nutrients in the future, nutrient retention should be taken into consideration.
The stability of 20 different types of polyphenols that are constituents of edible plants was evaluated under different pH conditions (in buffer solutions at pH 6.8, 7.4, and 8.3). Carnosol was the most unstable, followed by myricetin, quercetin, carnosic acid, nordihydroguaiaretic acid, baicalein, gallic acid, and hydroxytyrosol. They were more unstable at a higher pH, which may be attributed to their enhanced redox properties in alkaline solutions, determined by their antioxidant and prooxidant activity. The xanthine oxidase (XO) inhibitory activity of the reaction products under alkaline conditions was evaluated. XO activity was significantly inhibited by the product produced from gallic acid in pH 7.4 solution. The structural analysis of this reaction product revealed that a gallic acid dimer, purpurogallin-8-carboxylic acid, was formed and played a role in the resulting XO inhibitory activity.
Yacon (Smallanthus sonchifolius) is an herbal plant and its root has been historically consumed as a sweet vegetable in the Andes. With the research goal of establishing yacon leaves, grown in Japan, as a foodstuff with health benefits, we previously reported the antioxidant effects of yacon tea leaves using concentrated extracts. In this study, we determined the optimum conditions for regular hot-water extraction of yacon tea leaves, intended for normal consumption, aiming for higher activity in several antioxidant assays and total phenolic content (TPC). Response surface methodology was used to optimize the extraction by central composite design. Extraction temperature (ranging from 75.0 to 96.0 °C) and time (from 2.00 to 5.50 min) were set as the two independent variables. Based on a composite desirability value of 0.863, the hot-water extraction of yacon tea at 89.3 °C for 2.50 min was found to be the optimized condition providing higher antioxidant activity and TPC.
In this study, we investigated six minerals, amylose, soluble protein and total protein, total polyphenols contents, and antioxidant capacity for three black rice, two red rice and three white rice cultivars. The results showed that coloured rice varieties contained the higher minerals and polyphenols content than those of white rice. Besides, the study indicated that polyphenols contributed to accumulation of divalent and trivalent minerals, but little effect to monovalent minerals. Black- and red rice possessed the stronger antioxidant capacity than that of white rice, and red rice presented the highest among three different coloured rice varieties. Then the study showed that protein content slightly influenced accumulation of amylose. Besides, protein and amylose content both existed hardly in significant difference among different coloured rice varieties. Hence, this suggests that red- and black rice has higher levels of nutrition and stronger antioxidant capacity for one's health than white rice.