Fractionation and physicochemical characterization of dietary fiber of kenaf (Hibiscus cannabinus L.) seed.

BACKGROUND: Kenaf seeds are underutilized kenaf plant by-products, containing essential nutrients including dietary fiber (DF), which can be potentially utilized as food ingredients. The present study aimed to evaluate the physicochemical characteristics of kenaf seed fiber fractions extracted from kenaf seed. RESULTS: Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions. CONCLUSION: These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.

The effect of alkaline extraction and drying techniques on the physicochemical, structural properties and functionality of rice bran protein concentrates.

Rice bran protein concentrates (RBPC) were extracted using mild alkaline solvents (pH: 8, 9, 10). The physicochemical, thermal, functional, and structural aspects of freeze-drying (FD) and spray-drying (SD) were compared. FD and SD of RBPC had porous and grooved surfaces, with FD having non-collapsed plates and SD being spherical. Alkaline extraction increases FD's protein concentration and browning, whereas SD inhibits browning. According to amino acid profiling, RBPC-FD9's extraction optimizes and preserves amino acids. A tremendous particle size difference was prominent in FD, thermally stable at a minimal maximum of 92 °C. Increased pH extraction gives FD greater exposal surface hydrophobicity and positively relates to denaturation enthalpy. Mild pH extraction and drying significantly impacted solubility, improved emulsion properties, and foaming properties of RBPC as observed in acidic, neutral, and alkaline environments. RBPC-FD9 and RBPC-SD10 extracts exhibit outstanding foaming and emulsion activity in all pH conditions, respectively. Appropriate drying selection, RBPC-FD or SD potentially employed as foaming/emulsifier agent or meat analog.

Oilseed meals into foods: an approach for the valorization of oilseed by-products.

The excellent health benefits of oil extracted from seeds have increased its application in foods, pharmaceutical and cosmetic industries. This trend leads to a growing research area on their by-products, oilseed meals, to minimize environmental and economic issues. Examples of these by-products are soybean, peanut, kenaf seed, hemp, sesame, and chia seed meals. It is well known that soybean meals have wide applications in food and non-food industries, while other seed meals are not well established. Most oilseed meals are rich in health beneficial compounds and are potential sources of plant protein, dietary fiber, and antioxidants. Many studies have reported on the valorization of these by-products into value-added food products such as bakery and meat products to increase their nutritional and functional properties. These efforts contribute to the sustainability, development of novel functional food and support the zero-waste concept for the environment. This review aims to provide information on the composition of selected oilseed meals from soybean, peanut, hemp, kenaf, sesame and chia seeds, their potential applications in the bakery, meat, beverage, pasta, and other food products, and to highlight the issues and challenges associated with the utilization of oilseed meals into various food products.

Dietary Fiber: Fractionation, Characterization and Potential Sources from Defatted Oilseeds.

Dietary fiber (DF) has wide applications, especially in the food and pharmaceutical industries due to its health-promoting effects and potential techno-functional properties in developing functional food products. There is a growing interest in studies related to DF; nevertheless, there is less focus on the fractionation and characterization of DF. The characteristics of DF fractions explain their functionality in food products and provide clues to their physiological effects in food and pharmaceutical industrial applications. The review focuses on a brief introduction to DF and methods for its fractionation. It discusses the characterization of DF in terms of structural, physicochemical and rheological properties. The potential sources of DF from selected defatted oilseeds for future studies are highlighted.

Lipid oxidation and protein co-oxidation in ready-to-eat meat products as affected by temperature, antioxidant, and packaging material during 6 months of storage.

Ambient-storage-friendly, ready-to-eat (RTE) meat products are convenient in emergencies, such as earthquakes, flash floods and the current global Covid-19 lockdown. However, given the processing and long storage time of such food products, the lipid and protein components may be more susceptible to oxidation. Chicken serunding is a low-moisture, high-lipid, high-protein, RTE product that is prone to lipid oxidation and protein co-oxidation, causing product quality deterioration. The present study assessed the effects of storage temperature (25, 40, 60 °C), antioxidant (butylated hydroxyanisole, BHA), and multilayer packaging materials [metallised polyethene terephthalate (MPET) and aluminium] on the lipid oxidation and protein co-oxidation of chicken serunding during six months of storage. All lipid and protein markers elevated with increasing temperature (25 < 40 < 60 °C), indicating that storage of low-moisture meat at high temperature is not feasible. BHA was effective against lipid oxidation, as indicated by the significantly lower (p <0.05) extracted lipid content and delayed formation of malondialdehyde, a secondary lipid oxidation product. However, BHA is not effective against protein co-oxidation, as shown by the insignificant (p >0.05) effect on preventing tryptophan loss, protein carbonyl formation and Schiff base accumulation. MPET packaging with a superior light and oxygen barrier provided significant protection (p <0.05) compared to aluminium. In conclusion, low temperature (25 °C) storage of low-moisture, high-lipid, high-protein, cooked meat systems in MPET packaging is recommended for long-term storage to delay the progression of lipid oxidation and protein co-oxidation.

Physical properties, storage stability, and consumer acceptability for sourdough bread produced using encapsulated kombucha sourdough starter culture.

This study aimed to produce sourdough bread using an encapsulated kombucha sourdough starter culture without the addition of baker's yeast. The bioactive metabolites of kombucha sourdough starter and sourdough starter without kombucha were identified using 1 H-NMR analysis with multivariate analysis. The physical properties, including loaf volume, specific loaf volume, firmness, and water activity were determined following standard methods. The shelf life and consumer acceptability of the bread were also being evaluated. The principal component analyses showed the presence of 15 metabolites in kombucha sourdough starter. The major compounds that contributed to the differences from sourdough starter without kombucha were alpha-aminobutyric acid, alanine, acetic acid, riboflavin, pyridoxine, anserine, tryptophan, gluconic acid, and trehalose. The encapsulated kombucha sourdough starter increased the loaf volume (976.7 ± 25.2 mL) and specific loaf volume (4.38 ± 0.12 mL/g) compared to yeast bread. Thus, significant (P < 0.05) reduction was observed in the crumb firmness (116.07 ± 6.28 g) compared to traditional sourdough bread and yeast bread. The encapsulated kombucha sourdough starter extended the shelf life of bread by 5 to 10 days at room temperature. The sourdough bread prepared using the encapsulated kombucha sourdough starter demonstrated significantly (P < 0.05) higher taste and overall acceptability scores compared to the other bread. The findings indicate that the encapsulated kombucha sourdough starter is promising to produce functional sourdough bread with extended shelf life and improved quality. PRACTICAL APPLICATION: Encapsulated kombucha sourdough starter culture that appropriately refreshed can be used primarily as a dough leavening agent in the bread industry without the addition of baker's yeast. This starter culture applied in sourdough bread production extended the shelf life and improved the biological function of sourdough bread.

Effects of Storage Time and Temperature on Lipid Oxidation and Protein Co-Oxidation of Low-Moisture Shredded Meat Products.

Studies on the oxidative changes in meat-based, low-moisture, ready to eat foods are complicated due to complex food system and slow lipid-protein oxidative deterioration. The current study evaluates the oxidative changes over six months of storage on shredded beef and chicken products (locally known as serunding) for physicochemical analysis, lipid oxidation (conjugated dienes and malondialdehydes) and protein co-oxidation (soluble protein content, amino acid composition, protein carbonyl, tryptophan loss and Schiff base fluorescence) at 25 °C, 40 °C and 60 °C. The lipid stability of chicken serunding was significantly lower than beef serunding, illustrated by higher conjugated dienes content and higher rate of malondialdehyde formation during storage. In terms of protein co-oxidation, chicken serunding with higher polyunsaturated fatty acids (PUFA) experienced more severe oxidation, as seen from lower protein solubility, higher protein carbonyl and Schiff base formation compared to beef serunding. To conclude, chicken serunding demonstrates lower lipid and protein stability and exhibits higher rate of lipid oxidation and protein co-oxidation than beef serunding. These findings provide insights on the progression of lipid oxidation and protein co-oxidation in cooked, shredded meat products and could be extrapolated to minimize possible adverse effects arising from lipid oxidation and protein co-oxidation, on the quality of low-moisture, high-lipid, high-protein foods.