Vesna B. Vujasinović

CHARACTERISTICS OF BLACKBERRY AND RASPBERRY SEEDS AND OILS

This study is concerned with the determination of technological quality characteristics of dried pomaces, i.e. blackberry and raspberry seeds, along with the quality parameters, content of total carotenoids and chlorophyl and transparency of crude extracted oil (using organic solvent). Blackberry seeds (Rubus fruticosus L.) were obtained from a domestic variety Cacanska bestrna, while the raspberry seeds (Rubus idaeus L.) were of the variety Willamette. Oil content of the blackberry pomace was 13.97 and 14.34%, while the oil content of the raspberry pomace was 13.44 and 14.33% on dry basis (d.b.). In regard to technological characteristics of the pomaces, i.e. volumetric and specific weight, no considerably difference was found. However, a weight test for 1000 seeds showed a significant difference in weight: 3.5 g (d.b.) for the blackberry pomace and 1.5 g for the raspberry pomace (d.b.). Proximate analysis of blackberry seed oil showed that this oil had better quality since the FFA value was 3.43% (sample B1) and 3.53% (sample B2), while the peroxide value was 8.89 and 11.16 mmol/kg, respectively. Raspberry seed oil had higher FFA (8.59 and 8.83% for sample R1 and R2) and peroxide values (13.99 and 13.84 for sample R1 and R2) than the blackberry seed oil. Crude extracted blackberry seed oil had a brown-greenish color due to the high total chlorophyll content (around 3000 mg/kg dissolved in cyclohexane). Raspberry seed oil had a dark yellowishorange color, due to lower chlorophyll content (around 200 mg/kg) compared to the blackberry seed oil, while the content of total carotenoids was slightly higher in this oil (around 40 mg/kg) compared to the blackberry seed oil (33 mg/kg). [Projekat Ministarstva nauke Republike Srbije, br. TR 31014: Development of the new functional confectionery products based on oil crops]

Development of a Hull-Less Pumpkin (Cucurbita pepo L.) Seed Oil Press-Cake Spread

UNLABELLED A stable, oil-based spread rich in the omega-3 (ω-3) and omega-6 (ω-6) fatty acids was developed using a hull-less pumpkin seed (Cucurbita pepo L.) oil press-cake, a by-product of the pumpkin oil pressing process, along with cold-pressed hemp oil. Response surface methodology (RSM) was applied to investigate the effects of two factors, as the formulations compositional variables: a commercial stabilizer (X(1) ) and cold-pressed hemp oil (X(2) ) added to the pumpkin seed oil press-cake in the spread formulations. A central composite, 2-factorial experimental design on 5 levels was used to optimize the spreads where model responses were ω-3 fatty acids content, spreadability (hardness), oil separation, and sensory evaluation. The selected responses were significantly affected by both variables (P < 0.05). The spreads resembled commercial peanut butter, both in appearance, texture and spreadability; were a source of ω-3 fatty acids and with no visual oil separation after 1 mo of storage. An optimum spread was produced using 1.25% (w/w) of stabilizer and 80% of hemp oil (w/w, of the total added oil) which had 0.97 g of ω-3 fatty acids per serving size; penetration depth of 68.4 mm; oil separation of 9.2% after 3 mo of storage; and a sensory score of 17.5. PRACTICAL APPLICATION A use of by-products generated from different food processing technologies, where the edible waste is successfully incorporated as a value-added ingredient, has become a very important area of research to support global sustainability efforts. This study contributes to the knowledge of a product design process for oil-based spread development, where oil press-cake, a by-product of the oil pressing process of the naked pumpkin seeds, was used and where results have demonstrated that a new product can be successfully developed and potentially manufactured as a functional food.

Optimization of Hull‐Less Pumpkin Seed Roasting Conditions Using Response Surface Methodology

Response surface methodology (RSM) was applied to optimize hull-less pumpkin seed roasting conditions before seed pressing to maximize the biochemical composition and antioxidant capacity of the virgin pumpkin oils obtained using a hydraulic press. Hull-less pumpkin seeds were roasted for various lengths of time (30 to 70 min) at various roasting temperatures (90 to 130 °C), resulting in 9 different oil samples, while the responses were phospholipids content, total phenols content, α- and γ-tocopherols, and antioxidative activity [by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical assay]. Mathematical models have shown that roasting conditions influenced all dependent variables at P < 0.05. The higher roasting temperatures had a significant effect (P < 0.05) on phospholipids, phenols, and α-tocopherols contents, while longer roasting time had a significant effect (P < 0.05) on γ-tocopherol content and antioxidant capacity, among the samples prepared under different roasting conditions. The optimum conditions for roasting the hull-less pumpkin seeds were 120 °C for duration of 49 min, which resulted in these oil concentrations: phospholipids 0.29%, total phenols 23.06 mg/kg, α-tocopherol 5.74 mg/100 g, γ-tocopherol 24.41 mg/100 g, and an antioxidative activity (EC(50)) of 27.18 mg oil/mg DPPH.