Extrusion improved the physical and chemical properties of dietary fibre from bamboo shoot by-products

Bamboo shoot by-products are regarded as waste and environmental pollutant. This study aimed to improve the functional properties of dietary fibre from bamboo shoot by-products. After CO₂ extrusion, the particle size of CO₂-extruded bamboo fibre was 17.6% lower than that of the control, and its specific surface area was 2.85 times that of the control. The soluble dietary fibre content was significantly increased from 5.64 g/100 g to 11.05 g/100 g (P < 0.05), and the capacities for water holding, swelling and oil holding were remarkably improved. The cholesterol adsorption of CO₂-extruded bamboo fibre was increased from 96.54 μg g⁻¹ to 174.65 μg g⁻¹ (pH 7.0), and its nitrite ion adsorption capacity was increased from 503.33 μg g⁻¹ to 657.27 μg g⁻¹ (pH 2.0). In summary, the structural changes of bamboo fibre such as internal porosity, surface roughening and low crystallinity indicated that its functional properties were improved after CO₂ extrusion.     

Improved function of bamboo shoot fibre by high-speed shear dispersing combined with enzyme treatment

With the increase in global welfare, metabolic syndrome-related diseases seriously disrupt our quality of life. Balanced diet with low calories, low glycaemic index, and high dietary fibre such as bamboo shoot fibre is needed. Functional properties of dietary fibre can be improved by processing methods. Therefore, we compared the effect of three processing methods (high-speed shear dispersing, enzyme treatment and combined treatment) on the characteristics and functions of bamboo shoot fibres. Combined treatment resulted in high SDF content (10.15%), adsorption capacity of glucose (4.45–18.18 mmol g⁻¹), nitrite ion (505.49 μg g⁻¹ [pH 2.0]), and cholesterol (333.72 μg g⁻¹ [pH 2.0]). FTIR revealed that hydroxyl groups, sugar methylene and benzene rings of aromatic compounds existed in the treated bamboo shoots. The particle size (D₅₀) decreased from 383.90 to 30.65 μm. Honeycomb-like structure was also observed through SEM. Thus, proper processing of bamboo shoot fibres can improve their functions as food ingredients.     

Dietary fibre extracted from different types of whole grains and beans: a comparative study

Dietary fibre (DF) from different whole grains and beans (quinoa, buckwheat, highland barley, pea and mung bean) was extracted by enzymatic action. The components, crystallinity and properties were comparatively studied. Furthermore, we evaluated correlations between DF components and their crystallinity, thermal, physicochemical and functional properties. Results showed quinoa DF had highest polyphenol (25.58 mg GAE per 100 g), pectin (4.68%) and cellulose (52.34%) contents, crystallinity value (CV, 30.24%), ΔH (185.53 J g⁻¹), water-holding capacity (WHC, 5.35 g g⁻¹), α-amylase activity inhibition ratio (α-AAIR, 13.34%) and glucose absorption capacity (GAC), but lowest protein content (9.78%) and T_p (163.05 °C). Mung bean DF had highest lignin content (33.56%), fat adsorption capacity (4.73 g g⁻¹), and T_p (176.25 °C), but lowest CV (15.26%) and ΔH (132.15 J g⁻¹). Correlation analysis showed cellulose content had positive linear correlations with CV, ΔH, WHC, α-AAIR and GAC, but a negative correlation with T_p. The structure and properties of DF are largely attributed to cellulose content.     

Partial replacement of meat by sugar cane fibre: cooking characteristics,sensory properties of beef burgers and in vitro fermentation of sugar cane fibre

In this study, sugar cane fibre (SCF) partially replaced meat in beef burger formulations. The effects of SCF on cook yield, dimensional changes, sensory characteristics of beef burgers and in vitro gut fermentation characteristics were evaluated. Replacing beef with 1 to 5% SCF in burgers significantly increased cook yields from 13.8 ± 0.3 to 59.1 ± 0.3% due to its high water-binding capacity of 5.89 ± 0.08 g g⁻¹ and oil-binding capacity of 4.68 ± 0.03 g g⁻¹. The inclusion of SCF improved cooking properties whilst improving sensory characteristics. Burgers with 1% SCF had the highest overall acceptability. SCF was steadily fermented with a porcine faecal inoculum for up to 72 h, producing short-chain fatty acids. The characteristics of high water/oil binding and fermentability suggest that SCF has the potential to provide a range of dietary fibre benefits, and therefore deserves further study.     

Dynamic changes in flavonol glycosides during production of green,yellow, white,oolong and black teas from Camellia sinensis L. (cv. Fudingdabaicha)

Flavonol glycosides with low thresholds are important flavour substances in tea leaves. This study monitored the dynamic changes in flavonol glycosides during the production of different teas. The fresh leaves of cv. Fudingdabaicha with 15.77 mg g⁻¹ of total flavonol glycosides (TFG) were respectively processed into green, yellow, white, oolong and black teas. A reduction of TFG was observed for different teas, amongst which black tea contained the lowest level of TFG (9.83 mg g⁻¹), followed by oolong tea (11.96 mg g⁻¹), while green, yellow and white teas contained similar levels of TFG (~13.70 mg g⁻¹). Fixation was crucial to maintain the stability of flavonol glycosides due to its inactivation effect on enzymes at high temperature. Principal component analysis results indicated that flavonol glycosides were vulnerable to fermentation, and the stabilities of flavonol glycosides were related with aglycone and glycoside moiety.     

Polyphenolic composition,antioxidant and antiproliferative effects of wild and cultivated blackberries (Rubus fruticosus L.) pomace

The content of total polyphenolics, antioxidative capacity and antiproliferative activity were tested in wild and cultivated blackberry pomace. Wild blackberry pomace extract Tw2 showed the highest following contents: total polyphenolics (50.16 mg GAE g⁻¹ dw), flavonoids (7.73 mg Qc g⁻¹ dw), flavonols (6.63 mg Qc g⁻¹ dw) and total monomeric anthocyanins (13.40 mg Cy g⁻¹). Tw2 extract significantly inhibited free radicals: IC₅₀^DPPH = 127.76 μg mL⁻¹, IC₅₀^ABTS = 26.53 μg mL⁻¹ and IC₅₀ ^{˙ OH} = 168.62 μg mL⁻¹, and the growth of breast adenocarcinoma IC₅₀^MCF7 = 306.68 μg mL⁻¹ and cervix epitheloid carcinoma cell lines IC₅₀^HeLa = 315.49 μg mL⁻¹. Wild blackberry varieties had higher extraction yields, higher total polyphenolic contents and possessed stronger biological effects compared to cultivated blackberries (P < 0.05). All blackberry extracts showed high biological potential that could be attributed to high total polyphenols and flavonoids content and could be utilised as value-added functional food.     

Evaluation of oscillatory and shear strain behaviour for thermo-rheological plasticisation of non-ripened cheese curd: Effect of water,protein, and fat

Non-ripened cheese curd with different dry matter (34.5–47.0 g 100 g⁻¹), protein (13.4–30.4 g 100 g⁻¹), and fat (0.5–25.9 g 100 g⁻¹) contents were produced from pre-acidified milk (citric acid, pH 5.8) with different fat-to-protein ratios (0, 0.18, 0.33, 0.79, 1.60) and different curd cooking times (15 min, 30 min, 85 min). From small angle oscillatory temperature sweep and large strain capillary rheology shear experiments it was deduced that the protein content increases and fat decreases maximal loss tangent and storage modulus. This is discussed in relation to suggested changes in casein micelle voluminosity with temperature. A critical shear stress above which the flow behaviour changes from regular to melt fracture behaviour was observed. This is explained by shear jamming and the frequency dependency of the sol–gel transition.     

Impact of lecithin incorporation on gel properties of bigeye snapper (Priacanthus tayenus) surimi

Gelling characteristics of bigeye snapper (Priacanthus tayenus) surimi functionalised by lecithin at different concentrations were investigated. Lecithin at ≤1 g 100 g⁻¹ had no impact on breaking force and deformation (P > 0.05). Expressible drip tended to decrease with increasing lecithin level up to 1 g 100 g⁻¹. Lecithin at 1–3 g 100 g⁻¹ improved the whiteness (P < 0.05). Jointed clusters were formed in the gel microstructure with 1 g 100 g⁻¹ lecithin. Gel without and with 1 g 100 g⁻¹ lecithin had the same texture profile and likeness scores (texture, odour and flavour) (P > 0.05). Peroxide value, TBARS content and rancid odour score of gels were changed considerably during refrigerated storage (4 °C/polyethylene bag) for 15 days but lower values of all indices were noticeable in gel with lecithin. Therefore, lecithin at 1 g 100 g⁻¹ was the optimum concentration for stabilising the texture, improving the water holding capacity, whitening the colour and retarding the lipid oxidation of bigeye snapper surimi gel.     

Comparison of isoflavones composition in seed,embryo, cotyledon and seed coat of cooked-with-rice and vegetable soybean (Glycine max L.) varieties

In order to study the content and composition of isoflavones retained in soybean seed component, obtained each component part the embryo, cotyledon and seed coat tissues of nine different soybean varieties were analyzed for 12 isoflavones using high performance liquid chromatography with photo diode array detector (HPLC-PDA) and were compared to each other. A total average concentration of isoflavone was 2887 μg g⁻¹ in embryo, 575 μg g⁻¹ in whole seed, 325 μg g⁻¹ in cotyledon, and 33 μg g⁻¹ in seed coat. With respect to each tissue of soybean varieties, isoflavone content was highest in Geomjeongkong 2 embryo (5701 μg g⁻¹), Geomjeongolkong whole seed (1321 μg g⁻¹), Heugcheongkong cotyledon (951 μg g⁻¹), and Keunolkong seed coat (56 μg g⁻¹). Isoflavone was least present in Keunolkong embryo (341 μg g⁻¹), Hwaeomputkong whole seed (175 μg g⁻¹), Seonheukkong cotyledon (81 μg g⁻¹), and Seoklyangputkong seed coat (5 μg g⁻¹). Overall, embryo and seed coat of all nine varieties contained isoflavones at the highest and lowest level, respectively. Isoflavones accumulated in the order of malonylglycoside, glycoside, acetylglycoside, and aglycon, among which malonylglycoside was the most abundant form ranging from 66% to 79% of the total isoflavone content in all three tissues. The embryo of cooked-with-rice soybean with black seed coat appears to be the best source of isoflavone.     

Extraction of antioxidant and antimicrobial compounds from Inga marginata Willd bark and pulp using different extraction techniques and phytochemical characterization

This study aimed to identify the least aggressive and highest yield extraction method to obtain bioactive compounds from Inga marginata Willd fruits, determine the chemical components, and evaluate the extracts’' antimicrobial and cytotoxic activity. The extraction efficiency was expressed by the total phenolic and total flavonoid content and antioxidant activity (DPPH, IC₅₀, and ORAC) using conventional, ultrasound, and microwave-assisted extraction. The highest bioactive compound content was achieved using 5 min at 60 °C for total phenolic content (214.98 mg GAE g⁻¹), total flavonoid content (22.90 mg EQ g⁻¹), DPPH (45.98 μmol TEAC g⁻¹), inhibitory capacity (0.80 mg mL⁻¹), and ORAC (167.25 μmol Trolox g⁻¹) using ultrasonic extraction, and the extract inhibited the growth of all microorganisms tested. Thirteen chemical compounds were determined by ESI-ToF-MS, confirming the high phytochemical capacity of the extract. Lastly, the Inga extract showed no cytotoxicity at the concentrations used.     

Content of various elements in different parts of the tea plant and in infusions of black tea from Southern India

Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g⁻¹ tea) followed by P (700–1200 μg g⁻¹), Mg (300–700 μg g⁻¹), Ca and A1 (each 150–300 μg⁻¹), Mn (60–150 μg g⁻¹), Cu, Na, Si and Z n (each 6–50 μg g⁻¹), B, Ba, Cr, Fe, Ni and Pb (each Id μg g⁻¹), and Sr, Co and Gd (each <1μg g⁻¹). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.     

An integrated sustainable approach for the development of Kyoho skin functional tea

Kyoho (Vitis labruscana) skin is one of the valuable and eco-friendly agricultural waste and a potential source of phenolic compounds. Therefore, we attempted to develop Kyoho skin functional tea and evaluated its nutritional-functional properties as affected by drying temperatures (30, 40, 50 and 60 °C). Kyoho skin functional tea reported negligible protein (0.02 mg g⁻¹), fat (0.04–0.19%) and calories (0.36–0.70 cal g⁻¹). Total phenolic and flavonoid contents ranged from 0.25 to 0.56 mg GAE mL⁻¹ and 0.03 to 0.19 mg QE mL⁻¹, respectively. Kyoho skin functional tea showed functional properties including antioxidant activity (63.33–79.78%) and anthocyanins (0.25–0.34 mg per 100 mL). The sensory evaluation of Kyoho skin functional tea (dried at 40 °C) rated as acceptable (>6) with attractive colour (>6). Overall, these findings recommended the possibility of using Kyoho skin to develop functional teas, which may strengthen the global beverage industries.     

Process optimisation and physicochemical characterisation of enzymatic hydrolysates of proteins from co‐products of Atlantic Salmon (Salmo salar) and Yellowtail Kingfish (Seriola lalandi)

The aim of this study was to develop an enzymatic hydrolysis process of protein co‐products for two major commercial fish species in Australia: Atlantic salmon (AS) and Yellowtail kingfish (YTK). The outcomes are to produce high protein recovery of fish protein hydrolysates within controlled molecular weight ranges that display enhanced physicochemical properties of oil binding and emulsification. Three enzymes (Flavourzyme, Neutrase and Alcalase) were applied to processing co‐products. Protein recovery and physicochemical properties were evaluated with increasing hydrolysis time from 30 min to 180 min and ratio of enzyme to substrate (E/S) from 0.5% to 3.0%. In order to achieve a product with optimum emulsifying capacity (50 ± 0.6 m² g^?1), an E/S ratio of 0.6–1.3% Flavourzyme was applied for 30–111 min with a protein recovery of 55%; in order to achieve a product with optimum oil‐binding capacity (8.3 ± 0.3 g oil g hydrolysates^?1), an E/S ratio of 2.3–3.0% Flavourzyme was applied for 25–64 min with a protein recovery of 70%. YTK protein hydrolysates were further membrane‐fractionated into five fractions (>100 kDa, 50–100 kDa, 30–50 kDa, 10–30 kDa and <10 kDa), and of these, the 10–30 kDa exhibited the best properties of oil binding (19 ± 0.3 g oil g hydrolysates^?1) and emulsification (57 ± 0.7 m² g^?1). These results demonstrate the importance of enzymatic hydrolysis of seafood co‐products into high‐value ingredients for food products and processing.     

Effect of debittering and solid-state fermentation processes on the nutritional content of lupine (Lupinus mutabilis Sweet)

There is a growing interest in vegetable-based sources of proteins. Despite its high nutrient content, lupine has been rarely exploited as a protein source due to the presence of high levels of non-nutritive compounds such as alkaloids, which impart a bitter taste. Here, we evaluated the effect of debittering and solid-state fermentation on the nutritional contents of three lupine varieties (Lupinus mutabilis Sweet). These processes induced significant changes (P < 0.05) in the nutritional composition of the three lupine varieties (INIAP-450, INIAP-451 and Criollo) and increased the protein levels to 644.55 g kg⁻¹ (Criollo variety) and the levels of several constituent amino acids such as valine (54.62 g kg⁻¹), methionine (42.47 g kg⁻¹), isoleucine (59.27 g kg⁻¹) and leucine (76.32 g kg⁻¹). The ether extract of INIAP-450 showed increased levels (up to 244.03 g kg⁻¹); especially, monounsaturated fatty acids (559.78 g kg⁻¹) and polyunsaturated fatty acids (293.17 g kg⁻¹) were observed. The omega-6/omega-3 ratio in the debittered grain oil reached the minimum requirement established for good-quality oils (5/1). However, the levels of other components decreased, showing levels up to 13.04 g kg⁻¹ (total starch) in the Criollo variety, 22.62 g kg⁻¹ (resistant starch) in INIAP-450, 6.53 g kg⁻¹ (potassium) in INIAP-451, 46 g kg⁻¹ (iron) in INIAP-451 and 29.75 g kg⁻¹ (zinc) in INIAP-450.     

Effects of carboxymethylation,hydroxypropylation and dual-enzyme hydrolysis combination with heating on in vitro hypoglycaemic properties of coconut cake dietary fibres

Effects of carboxymethylation, hydroxypropylation and dual-enzyme hydrolysis combined with heating on in vitro hypoglycaemic properties of coconut cake dietary fibre (CCDF) were studied. Results showed that all the three modification methods could effectively improve (P < 0.05) the glucose-adsorption ability (GAA), glucose dialysis retardation index (GDRI), α-glucosidase and α-amylase inhibition activity of CCDF. The highest GAA (4.45–4.93 mm  g⁻¹), GDRI (85.09–86.94% mm  g⁻¹) and α-glucosidase inhibition activity (16.39–19.37%) were found on CCDFs modified by hydroxypropylation and carboxymethylation, attributed to the increased soluble dietary fibre content, viscosity and water retention and swelling capacity. Moreover, CCDF treated by enzymatic hydrolysis combined with heating demonstrated the highest α-amylase inhibition activity (53.95%), attributed to the high specific surface area, more porous surface structure and formation of fibre–amylase complex proved by fluorescence spectroscopy. These results suggest that the modified CCDFs could be used as low-calorie functional ingredients in food or other industries.     

Evaluation of various Bacillus coagulans isolates for the production of high purity L-lactic acid using defatted rice bran hydrolysates

Defatted rice bran (DRB) constitutes an abundant by-product stream, generated during rice milling and subsequent bran oil extraction. Enzymatic hydrolysis of starch and protein content in DRB was optimised in terms of solid loading. Among the four solid loadings evaluated (10%, 15%, 20% and 25%), the hydrolysate derived from 20% solids resulted in the highest concentration of glucose (82.3 g L⁻¹) and free amino nitrogen (234.8 mg L⁻¹). The fermentability of the hydrolysate was evaluated via screening of sixteen isolates. All the strains were able to grow and produce high purity L-lactic acid, utilising the DRB as sole carbon and nutrient source. Among the studied strains, the Bacillus coagulans A107 isolate presented the most promising results in terms of final lactic acid concentration (75.9 g L⁻¹), yield (0.90 g g⁻¹) and productivity (2.7 g L⁻¹ h⁻¹). The results of this study indicate that DRB could be employed as an inexpensive, alternative substrate for L-lactic acid production.     

Mercury speciation in the muscle of two commercially important fish,hake (Merluccius merluccius) and striped mullet (Mullus barbatus) from the Mediterranean sea: estimated weekly intake

Total mercury and methylmercury concentrations were measured in the muscle tissue of two fish species from the Ionian and Adriatic seas. Higher total mercury and methylmercury concentrations were detected in striped mullet (Mullus barbatus), a benthic species (Ionian sea: Hg=0.40 μg g⁻¹ wet wt, MeHg=0.40 μg g⁻¹ wet wt; Adriatic sea: Hg=0.49 μg g⁻¹ wet wt, MeHg=0.44 μg g⁻¹ wet wt), than in hake (Merluccius merluccius), a pelagic species (Ionian sea: Hg=0.09 μg g⁻¹ wet wt, MeHg=0.09 μg g⁻¹ wet wt; Adriatic sea: Hg=0.18 μg g⁻¹ wet wt; MeHg=0.16 μg g⁻¹ wet wt). Total mercury residues were determined in all samples of both species from the Adriatic sea, while levels below the limit of detection were registered in 25% and 11%, respectively, of striped mullet and hake samples from the Ionian sea. In 18.8% and 22.2% of striped mullet samples from the Ionian and Adriatic seas, respectively, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg=0.5 μg g⁻¹ wet wt). In the two different species, mercury was present almost completely in the methylated form with mean percentages between 60% and 100%. The estimated weekly intake for total mercury was below the established the provisional tolerable weekly intake (PTWI) for both species, though their consumption provides a methylmercury intake above the WHO safety limit.     

Pectin recovery from apple pomace: physico-chemical and functional variation based on methyl-esterification

This study explored the valorisation of apple pomace by extracting pectin with both high and low degrees of esterification (DM). Two types of pectin were extracted with a DM of 43.29% being low methoxyl (LM) pectic polysaccharide and high methoxyl (HM) pectin with a DM of 65.88%. HM pectin was characterised by a WHC and OHC of 1.3 g g⁻¹ and 0.4 g g⁻¹, respectively, compared to 0.32 g g⁻¹ and 0.14 g g⁻¹, respectively, for LM pectic polysaccharide. HM pectin possessed greater purity indicated by 69.18% GalA, whereas LM pectic polysaccharide possessed 41.26% GalA. HM pectin revealed better functionality in terms of high emulsifying activity which was concentration-dependent, and emulsion stability than LM pectic polysaccharide. The solubility of HM pectin was 90.8%, which is preferable for various industrial applications. LM pectic polysaccharide was characterised by a higher % radical-scavenging activity in a concentration-dependent manner. XRD analysis revealed LM pectic polysaccharide to possess higher crystallinity (53%) and SEM analysis revealed its surface to be rough and coarse.     

Hydration of casein micelles and caseinates: Implications for casein micelle structure

By studying the hydration of casein micelles using a variety of techniques, a distinction could be made between water that appeared bound by the protein (∼0.5 g g⁻¹ protein), water associated with the κ-casein brush (∼1.0 g g⁻¹ protein) and water entrapped in the casein micelles (∼1.8 g g⁻¹ protein), yielding a total micellar hydration of ∼3.3 g g⁻¹ protein, in line with casein micelle voluminosity derived from intrinsic viscosity measurements. For caseinate particles, however, the main contributor to intrinsic viscosity was not protein hydration but the non-spherical particle shape. These non-spherical particles in caseinate are likely to be naturally present as primary casein particles (PCP) in casein micelles. PCP could be used to build casein micelles by controlled introduction of micellar salts. Based on the findings of this study, casein micelles could be described as a porous network of non-spherical PCP linked by calcium phosphate nanoclusters.     

A new nanofibrillated and hydrophobic grafted dietary fibre derived from bamboo leaves: enhanced physicochemical properties and real adsorption capacity of oil

Dietary fibre (DF) has been used for enhancing health benefits for centuries. In this study, an innovative nanofibrillated cellulose (NFC) was obtained by the combined application of high‐density steam flash‐explosion and enzymatic hydrolysis of bamboo leaves. The NFC prepared in this study was characterised by long, well‐defined and distinct NFC fibres, exhibiting excellent functional properties (water retention capacity: 20 g water g^?1, swelling capacity: 97 mL g^?1, oil‐holding capacity: 13 g oil g^?1, and higher adsorption of bile acids and cholesterol). Octenyl succinic anhydride (OSA) was further successfully grafted onto the NFC to improve its hydrophobicity. Thus, the oil‐holding capacity of the NFC reached 18.5 g oil g^?1 and the adsorption of bile acids and cholesterol increased twofold. A gastrointestinal digestion experiment further showed that the nanofibrillated and hydrophobic grafted dietary fibre represented a high‐quality dietary supplement providing enhanced health benefits, highlighted by the strong ability to absorb oil. These results indicate that the OSA‐NFC has a great potential for use as a functional ingredient in food products.