Physicochemical properties of pectin from green jelly leaf (Cyclea barbata Miers)

The water extract of Green Jelly leaves (GJL) obtained by crushing the leaves in water (1:40) was capable of forming a gel at room temperature. The composition of GJL consisted mainly of carbohydrate (∼70w/w), protein (∼13% w/w) and minerals (∼6% w/w). The mineral portion consisted of mainly calcium (∼1.2% w/w), zinc (∼0.12% w/w) and magnesium (∼0.11% w/w). The isolated polysaccharide fraction (∼42.6% w/w) consisted of mainly galacturonic acid (∼35.8% w/w) and neutral sugars (∼6.8% w/w), with a weight-average molecular weight of ∼4.4×10⁵g/mol. The results obtained by Fourier Transform Infra-Red (FTIR) showed that GJL polysaccharide fraction had a fairly similar FTIR fingerprint as the commercial low-methoxyl pectin (LMP). The degree of esterification of the polysaccharide changed drastically (from 97% to 10%) depending on the temperature used during the extraction process. The zeta potential of the extracted polysaccharide showed high negative charged as compared to the commercial LMP but close to sodium alginate. The study showed that the gelation was divalent cation-mediated and probably facilitated by the low degree of esterification which reduced steric hindrance from the methyl ester groups.

Evaluating the effects of insoluble dietary fibres on pea protein-based extruded meat analogues

Date fruit (Phoenix dactylifera L.) fibre, a by-product from the date syrup industry, is rich in nutrients and has been increasingly explored as a value-added ingredient for industrial applications. This study investigated the incorporation of date dietary fibre (DF) in pea protein isolate (PPI)-based meat analogues (HMMA) using high-moisture extrusion as a structuring technique. The DF amount was varied at five different concentrations: 0, 5, 10, 20 and 30 % w/w. The moisture content of the HMMAs reduced significantly, as fibres could facilitate the binding of free water. As a result, the addition of DF reduced the thermal stability of HMMAs, as shown by the earlier shifting of water evaporation temperature. Rheological results indicated that the elastic properties of HMMAs were lower with 5 to 10 % DF addition, indicating the formation of a brittle network, signified by an increase in hardness and chewiness. The inclusion of 5 to 10 % DF significantly increased the fibrousness of HMMAs, as shown by the increase in the degree of texturization, which was contributed by protein-fibre and fibre-fibre interaction, which bridged the protein network closer. This study shows the potential of DF influencing the fibrous formation in meat analogues produced using PPI as the primary ingredient.

Performance of composite blends comprising date fruit (Phoenix dactylifera L.) insoluble fibers, pea and wheat proteins to structure hybrid meat analogue

This study investigates the physicochemical properties of plant-based composites to develop hybrid meat analogue (HMA) patties. The composite comprised five formulations where date insoluble fibers (DF) and potato starch (PS) were varied with different ratios (DF:PS): 0:13 (F1); 2.5:11.5 (F2); 5:8 (F3); 7.5:5.5 (F4) and 10:3 (F5). The results indicated that DF variation significantly influenced HMA patties' water retention, protein content, cooking loss, pH, texture and colour. The HMA moisture content reduced with increasing DF amount in the formulation, due to water retention by DF. Addition of DF also reduced the HMA cooking loss and softened the patty texture. The patty thermal stability decreased with increasing DF amount in the formulation, shown by a gradual decrease in the endothermic peak temperatures. Protein content was enhanced due to additional protein from DF, where the Fourier transform infrared spectra confirmed the presence of protein secondary structure. The patties' meaty colour was more intense with increasing date fiber and was further enhanced by the heating process. The G' increased with increasing DF amount, suggesting DF strengthened the gel network by increasing water retention in the gel matrix and the formation of fiber-fiber network, leading to compacting the patty structure, which was shown clearly in HMA microstructure. These findings highlight DF's potential as a value-added functional ingredient for enhancing the textural and structural attributes of HMAs and expanding the application of DF in food systems.

Evaluating the effects of insoluble date fruit (Phoenix dactylifera L.) fibers on meat analogue patties composed of pea and wheat protein isolates

This study aimed to evaluate the effects of date pomace fibers (DF) on the physicochemical properties of plant-based ground patty analogues. Previously optimized pea and wheat protein isolates were incorporated with varying concentrations of DF, i.e., 0 %, 2.5 %, 5 %, 7.5 %, and 10 % w/w. The addition of DF increased water retention in the patties, leading to subsequent changes in the patty structure. Frequency sweep results confirmed that the presence of DF contributed to structural stability, where patties exhibited more solid-like characteristics and stronger internal bonds, which also increased hardness from ∼65 g to 160-175 g. This could positively correlate with the brittleness of the patties, where large deformation results showed that high DF formulations were more brittle, which reduced springiness, as evident in DF7.5 (from ∼2 mm in DF0 to 1.89 mm in DF7.5). The microstructure revealed that high DF content increased patty fibrousness and led to a uniform structure. Therefore, high DF concentrations seemed to positively impact the analogue structure. DF also contributed to patty analogue color by imparting brown-red tones which may result in a closer appearance to conventional beef patties. This study establishes a foundation for further studies to be conducted on determining the optimum DF concentration that yields patty analogues with desirable structure as well as appearance.